Lots of classes in org.eclipse.xtext.example.gmf.diagram.edit.part

Activator:
- Workaround for bug http://bugs.eclipse.org/bugs/show_bug.cgi?id=281014

MANIFEST.MF:
- Added dependencies to 
	org.eclipse.gmf.runtime.diagram.core
	org.eclipse.xtext.example.gmf.diagram
	org.eclipse.gmf.runtime.diagram.ui
	org.eclipse.xtext.example.gmf.ui
	com.google.guice
	
plugin.xml
- Added EditPartProvider

