Installed IntelliJ 16 EAP - Idea Platform Plugin Project won't load plugin in sandbox

After installing IntelliJ 16 EAP, my plugin project will no longer get loaded into the sandbox when I run it.  Even worse, if I go back and try and run it in IntelliJ 15, it no longer works either.  Is there some cache I have to clear?  How do I toubleshoot this?

Here are the contents of my idea.log file in the plugins-sandbox after starting up:

2015-12-22 10:57:42,363 [    229]   INFO -        #com.intellij.idea.Main - ------------------------------------------------------ IDE STARTED ------------------------------------------------------
2015-12-22 10:57:42,401 [    267]   INFO -        #com.intellij.idea.Main - IDE: IntelliJ IDEA (build #IU-143.1184.17, 07 Dec 2015 00:00)
2015-12-22 10:57:42,401 [    267]   INFO -        #com.intellij.idea.Main - OS: Mac OS X (10.11.1, x86_64)
2015-12-22 10:57:42,401 [    267]   INFO -        #com.intellij.idea.Main - JRE: 1.8.0_31-b13 (Oracle Corporation)
2015-12-22 10:57:42,401 [    267]   INFO -        #com.intellij.idea.Main - JVM: 25.31-b07 (Java HotSpot(TM) 64-Bit Server VM)
2015-12-22 10:57:42,407 [    273]   INFO -        #com.intellij.idea.Main - JVM Args: -Xmx512m -Xms256m -XX:MaxPermSize=250m -ea -Xbootclasspath/a:/Applications/IntelliJ IDEA 15.app/Contents/lib/boot.jar -Didea.config.path=/Users/mbrocato/Library/Caches/IntelliJIdea15/plugins-sandbox/config -Didea.system.path=/Users/mbrocato/Library/Caches/IntelliJIdea15/plugins-sandbox/system -Didea.plugins.path=/Users/mbrocato/Library/Caches/IntelliJIdea15/plugins-sandbox/plugins -Didea.classpath.index.enabled=false -Didea.smooth.progress=false -Dapple.laf.useScreenMenuBar=true -Didea.launcher.port=7533 -Didea.launcher.bin.path=/Applications/IntelliJ IDEA 15.app/Contents/bin -Dfile.encoding=UTF-8 -Xmx1500m -XX:MaxPermSize=256m
2015-12-22 10:57:42,407 [    273]   INFO -        #com.intellij.idea.Main - ext: /Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/ext: [cldrdata.jar, dnsns.jar, jfxrt.jar, localedata.jar, meta-index, nashorn.jar, sunec.jar, sunjce_provider.jar, sunpkcs11.jar, zipfs.jar]
2015-12-22 10:57:42,407 [    273]   INFO -        #com.intellij.idea.Main - ext: /System/Library/Java/Extensions: [AppleScriptEngine.jar, dns_sd.jar, j3daudio.jar, j3dcore.jar, j3dutils.jar, jai_codec.jar, jai_core.jar, libAppleScriptEngine.jnilib, libJ3D.jnilib, libJ3DAudio.jnilib, libJ3DUtils.jnilib, libmlib_jai.jnilib, mlibwrapper_jai.jar, MRJToolkit.jar, vecmath.jar]
2015-12-22 10:57:42,407 [    273]   INFO -        #com.intellij.idea.Main - ext: /usr/lib/java: [libjdns_sd.jnilib]
2015-12-22 10:57:42,422 [    288]   INFO -        #com.intellij.idea.Main - JNA library loaded (64-bit) in 15 ms
2015-12-22 10:57:42,424 [    290]   INFO -        #com.intellij.idea.Main - initializing environment
2015-12-22 10:57:42,426 [    292]   INFO - .intellij.util.EnvironmentUtil - loading shell env: /bin/bash -l -i -c '/Applications/IntelliJ IDEA 15.app/Contents/bin/printenv.py' '/private/var/folders/1h/0z9hww_9141bslc0s3bgxf440000gp/T/intellij-shell-env.0.tmp'
2015-12-22 10:57:43,167 [   1033]   INFO - .intellij.util.EnvironmentUtil - shell environment loaded (57 vars)
2015-12-22 10:57:43,835 [   1701]   INFO - llij.ide.plugins.PluginManager - 126 plugins initialized in 563 ms
2015-12-22 10:57:43,837 [   1703]   INFO - llij.ide.plugins.PluginManager - Loaded bundled plugins: ASP (0.1), Android Support (10.1.3.0), Ant Support (1.0), Application Servers View (0.2.0), AspectJ Support (1.2), Bytecode Viewer (0.1), CFML Support (3.53), CSS Support (143.SNAPSHOT), CVS Integration (11), ClearCase Integration (2.0), Cloud Foundry integration (1.0), CloudBees integration (1.0), CoffeeScript (2.0), Copyright (8.1), Coverage (143.SNAPSHOT), Cucumber for Groovy (999.999), Cucumber for Java (999.999), DSM Analysis (1.0.0), Database Tools and SQL (1.0), Eclipse Integration (3.0), EditorConfig (1.0), Emma (143.SNAPSHOT), Flash/Flex Support (1.0), FreeMarker support (1.0), GWT Support (1.0), Geronimo Integration (1.0), Gherkin (999.999), Git Integration (8.1), GitHub (143.1184.17), GlassFish Integration (1.0), Google App Engine Integration (1.1.4), Gradle (143.1184.17), Grails (9.0), Groovy (9.0), Guice (8.0), HAML (143.SNAPSHOT), HTML Tools (2.0), Heroku integration (1.0), Hibernate Support (1.0), I18n for Java (143.1184.17), IDEA CORE (143.SNAPSHOT), IntelliLang (8.0), J2ME (1.0), JBoss Arquillian Support (1.0), JBoss Drools Support (1.0), JBoss Integration (1.0), JBoss Seam Pageflow Support (1.0), JBoss Seam Pages Support (1.0), JBoss Seam Support (1.0), JBoss Support (1.0), JBoss jBPM (2.0.0), JSR45 Integration (1.0), JUnit (1.0), Java Bytecode Decompiler (0.1), Java EE: Batch Applications (1.0), Java EE: Bean Validation Support (1.1), Java EE: Contexts and Dependency Injection (1.1), Java EE: EJB, JPA, Servlets (1.0), Java EE: JMS, JSON Processing, Concurrency, Transaction  (1.0), Java EE: Java Server Faces (2.2.X.), Java EE: RESTful Web Services (JAX-RS) (1.0), Java EE: Web Services (JAX-WS) (1.9), Java EE: WebSockets (1.0), Java Server Pages Integration (1.0), JavaFX (1.0), JavaScript Debugger (1.0), JavaScript Intention Power Pack (0.9.4), JavaScript Support (1.0), Jetty Integration (1.0), Kotlin (1.0.0-beta-2428-IJ143-18), LESS support (143.SNAPSHOT), Maven Integration (143.1184.17), Maven Integration Extension (143.SNAPSHOT), OpenShift integration (1.0), Osmorc (1.4.7), Perforce Integration (2.0), Persistence Frameworks Support (1.0), Playframework Support (1.0), Plugin DevKit (1.0), Properties Support (143.SNAPSHOT), QuirksMode (143.SNAPSHOT), REST Client (143.SNAPSHOT), Refactor-X (2.01), Remote Hosts Access (0.1), Resin Integration (8.1), SASS support (143.SNAPSHOT), SSH Remote Run (0.1), Settings Repository (143.1184.17), Spring AOP/@AspectJ (1.0), Spring Batch (1.0), Spring Boot (1.0), Spring Data (1.0), Spring Integration Patterns (1.0), Spring MVC (1.0), Spring OSGi (1.0), Spring Security (1.0), Spring Support (1.0), Spring Web Flow (1.0), Spring Web Services (1.0), Spring WebSocket (1.0), Spy-js (999.999), Struts 1.x (2.0), Struts 2 (1.0), Stylus support (999.999), Subversion Integration (1.1), TFS Integration (999.999), Tapestry support (1.0), Task Management (1.0), Terminal (0.1), TestNG-J (8.0), Thymeleaf (1.0), Time Tracking (1.0), Tomcat and TomEE Integration (1.0), UI Designer (143.1184.17), UML Support (1.0), Vaadin Support (1.0), Velocity support (1.0), W3C Validators (2.0), WebLogic Integration (1.0), WebSphere Integration (1.0), XPathView + XSLT Support (4), XSLT-Debugger (1.4), YAML (143.SNAPSHOT), ZKM-Unscramble (1.0), dmServer Support (0.9.5), hg4idea (10.0)
2015-12-22 10:57:44,415 [   2281]   INFO - ellij.util.io.PagedFileStorage - lower=100; upper=500; buffer=10; max=1377304576
2015-12-22 10:57:44,438 [   2304]   INFO - pl.local.NativeFileWatcherImpl - Starting file watcher: /Applications/IntelliJ IDEA 15.app/Contents/bin/fsnotifier
2015-12-22 10:57:44,445 [   2311]   INFO - pl.local.NativeFileWatcherImpl - Native file watcher is operational.
2015-12-22 10:57:45,380 [   3246]   INFO -   #com.intellij.AbstractBundle - Cannot load resource bundle from *.properties file, falling back to slow class loading: com.intellij.javaee.heroku.cloud.HerokuBundle
2015-12-22 10:57:45,413 [   3279]   INFO - rains.ide.BuiltInServerManager - built-in server started, port 63343
2015-12-22 10:57:46,627 [   4493]   INFO - plication.impl.ApplicationImpl - 96 application components initialized in 3355 ms
2015-12-22 10:57:46,641 [   4507]   INFO - .intellij.idea.IdeaApplication - App initialization took 5079 ms
2015-12-22 10:57:46,918 [   4784]   INFO - ellij.concurrency.JobScheduler - 50 ms execution limit failed for: com.intellij.a.a.a.a$b@11c78ea3; elapsed time was 63ms