Remove models/roles and return to fat models

After half of year with models roles I'd like to remove them from system
Reasons below: 
* its difficult to define where method goes (role or model)
* roles are closely connected to model fields so changing model requires changing some or roles
* its easily to duplicate method already defined in another role
* testing roles requires a model anyway
* it is complicated to search for method having few roles

So I suggest to return to fat models + libs

I saved Vote, IssueCommonality, StaticModel as libs.  Also I am going to extract Repository from project in future in separate class in libraries

Feedback from core team is appreciated