added GroupService to simplify group management
Merge pull request #2 from mswiderski/group-service

added GroupService to simplify group management
Delete rogue file.. uberfire-backend-commons no longer exists
Ensure AppSetup is ran first. Move creation of FileSystems to server.
Remove redundant field from EntryPoint
Fix caching problem.
Update Errai to 2.3.0.Final for Beta2