UML plugin RFE: Add packages

I think that adding support for packages combined with the dependency discovery would make
the sUML plugin even better.


- on right click show 'Add classes recursively' and 'Add package'
- option to 'Add refferenced packages' to diagram this will add the
packages only and not classes
- show dependency arrows from all classes importing classes from the package
- add option not to show arrows to package if the class is already in the diagram
- show interpackage dependencies (this should be made an option)

BTW congratulations for the great job you've done so far :)

Dimiter