Including partial package tree (we need it!)

To refresh the memory of this argument:
- in 3.0.x it was possible to include a subpackage as a source
in a project (e.g. com.xxx.tools) and everything worked OK
- this is not possible anymore in EAP builds

One of the arguments used was that marking a src folder to correspond
to a particular package in not consistent with the overall
module configuration strategy.

That is apparently not true anymore - the web module configuration
allows to add a folder (similar to "add as source") to be "web root"
while possibly saying which deployment folder this one corresponds to.

See for example:
http://www.intellij.net/servlet/JiveServlet/download/4-63332-661237-2773/new-setup.gif
from
http://www.intellij.net/forums/thread.jsp?forum=4&thread=63332&tstart=0&trange=50#661237

(hope Robert doesn't have the GIF copyrighted)

r.