[Web] URBNG-66 Login and authorization + URBNG-77 Create new task + CSS changes

Added:
 - login system without 'stay logged in' option yet ('Remember me')
 - registration process that creates new user account and sends confirmation e-mail with authorization token (in link form) to the user
 - activation of the created account (only by link send to the user) with proper notifications (e.g. when the account has been activated earlier)
 - logout system

Changes:
 - new actions composition associated with play2-auth module
 - protection for the resources that prevents the access for unauthorized users (prevents one logged user to see or modify not their games)
 - switching the view of login form to 'logged in as' after logging in
 - operator's table has been modified to keep more informations about the user
 - e-mail address is now the unique ID of the user (used in logging in process)
 - captcha validation works (visually it's a bit different from the one planned by UX group, but reCaptcha has a length of two words and it needs more space to be readable by the user)
 - fully validated authentication system (if an account has not been activated yet, it won't log the user in but it shows an appropriate message and a possibility to send the activation token again)
 - CSS for main page (not complete)
 - CSS for games list
 - CSS for headers and navigation bar
 - CSS for game creator (not complete)
 - just a few new tests and updates for the old ones (will be more in next commit)

Graphics used in this version must be changed in the future (for a better quality issue)

Missing:
 - JS validation of forms (registration and login forms are validate server side only, it will be extended to JS validation for better user experience)
 - Remember me functionality ('remember me' checkbox is disabled for now, it will be changed later)
 - More tests for current functionality