Back buttons implemented
Some file structure organisation.
Registration and login implemented.
Added user menu buttons on main screen.
Merge branch 'master' into ershov

* master:
  Added user menu buttons on main screen.
  Registration and login implemented.
  Some file structure organisation.
  Back buttons implemented

Conflicts:
	src/Erundopel/Erundopel/AddContentChooseViewController.m
	src/Erundopel/Erundopel/AddContentChooseViewController.xib