Remove all unused build references.

Remove references to empty plugin.xml's, and delete them.
Updating PyDev version to match release version.
Remove all retroweaver stuff.

It was not used for long time and there was even preGenerate task that
was unzip and zip plugins and doing no other modification which is also
removed.

Change-Id: I3f1a807baa48d701292f3e938cc33a2761d4e67f
Providing a way to listen to lifecycle changes in PyUnit runs.
Remove empty plugin.properties files.

There remain some empty plugin.properties files that were not removed
last commit. Remove them now.
Merge pull request #9 from akurtakov/development

Remove all retroweaver stuff.
Merge pull request #11 from AndrewFerr/aferrazz_dev

More cleanup
Merge branch 'ticket109' of https://github.com/Cito/Pydev into Cito-ticket109