Fix I18n.enforce_available_locales deprecation warning

Thanks to http://stackoverflow.com/questions/20361428/rails-i18n-validation-deprecation-warning
Fix comment on join requests, hide when empty, and more tests

Comment was not in the list of allowed attributes.
Added more tests for it and a few pending specs for join requests that should
be implemented later.

refs #1278
Less scary error pages, visual improvements

Less red. Makes the pages more normal, not "screaming" to the user.
Also changed a few strings and a bit more tests.

refs #1203
Add extra permited parameter to posts controller
Change find syntax to where in spaces#webconf_room
Some refactorings and new rails4 params in private_messages
Put :confirm inside :data. refs #1354
User after_create and not save for new_activity in private_message
Feature tests for space listing
Prevent error when accessing 'my_spaces' logged out
Forbid admins from disapproving and disabling admins + feature tests
Admins can edit the :superuser flag, unless it's their own account
Configurations for mweb-events calendar locales
Remove unused methods in posts controller
Update mweb-events refs #1305 refs #1306
Merge remote-tracking branch 'origin/branch-v2' into branch-v2-bootstrap3

Conflicts:
	Gemfile.lock
	app/assets/stylesheets/app/errors/_all.css.scss
	app/views/my/_webconference_room.html.haml
Better modals for bootstrap 3

Fixing some conflicts between the lib bootstrap-modal and bootstrap 3.

refs #1087
Make copyable-field work with boostrap 3

And made the modal be created via javascript and not be inserted by default
in all pages.

refs #1087