[api] remove more to_s on strings

They are of course completely harmless, but I know how the copy&paste
disease spreads nonsense
[dist] update gem versions

This brings jquery-ui-rails, jquery-rails is no longer a catch all
[admin] add a small warning for the new source cleanup feature
[api] check for invalid specified review owners on review state change
[webui] Ingore maintenance incident projects in involved_projects
[dist] Fix 01ca0d2b80216684bd0fedcdab945d424e84f7f8 mysql path.
[api] allow to track issues in attributes (Fate #315168)
[api] display issues defined via attributes in view=display and introduce default attribute OBS:Issues
[api] migration id part for last commit
[api] support searching for issues in packages when defined via an attribute
[api] initial porting to rails 4
[dist] use rvm 2.0.0 to test OBS
[webui] initial porting to rails4
[dist] update to the next delayed_job beta
[backend] bs_publish: regex for published hooks is now auto-anchored left, sort keys for defined order

As mentioned by Michael Schroeder:

- auto-anchored regex left as used in all other configs
- sorting keys in publishedhooks
- use $$publish_prp instead of $prp

Conflicts:
	src/backend/bs_publish
[webui] drop dated README file, it confuses new assetts generation
[api] fix database migration with rails 4
[api] fail fast and obvious when /proc or /dev is not mounted
[api] use defined ordering for user/group role definitions in project and package meta

We did depend on the database sql result order so far
[api] do not depend on metadata order from createrepo