build: fix p2 publishing and product assembly
small fixes
fix Rakefile
fix publish symlinks
publish even zip with update sites
publish: generate version info files
1254 - macro definitions not found if space between name and comma
sync some extension points with their plugin names
remove unused code
remove dummy command reference in ui/plugin.xml
make engine access happen via the implemented services instead of a large facade
make ErlangXref a normal class (not static)
use ErlangEngine as a hub for retrieving all services
fix inconsistencies with ErlangEngine
code cleanup
move getStateDir from Modelcore to ErlangEngine
make ErlideOpen available through OpenService
make sure engine is only created once
move ErlideDoc to OtpDocService
merge engine work