limits principals returned by the autocompleter to only active or registerd
cleaning up unused code, rewriting scopes
updates changelog
adds a user pagination controller for timelines
removes scopes also present on the superclass
handles principals pagination controller same as users
moves pagination to api::v2
streamlines pagination specs, enables using index action
moves remaining paginations under api/v2/pagination scope
removes outdated routes
Merge remote-tracking branch 'origin/feature/rails3' into fix/unfitting_principals_in_auto_completer

Conflicts:
	doc/CHANGELOG.md
Merge pull request #515 from opf/fix/unfitting_principals_in_auto_completer