Removed unused maven plugin (we don't use IDEA UI Designer forms anymore)
ERRAI-430

Note: ClientMessageBusImpl *cannot* be directly injected anymore. As a concrete implementation that matches the type of the top-level provider, it is disabled by default.
- fix to thread-race problems with new parallel generator framework
- cleaned up the generator framework
- fixed bugs in async bean manager (generator was calculating wrong variable names for beans looked up by interfaces instead of concrete types)