Fix tooltips with partial text

Some tooltips had a long text that was being partially shown because it was
forced to be in a single line.
Prevent notifications for being shown more than once, refs #966
Refactor base.js as a class to rebind events when modals are opened

It still has a lot of simple methods and bindings, but they are now all organized
in a method that's called when modals are shown to bind the events again.
Bindings are also scoped and unbound before binding them again.
Add gem configatron, refs #800

For now only to store the available locales, but should be used in the future
for a lot more.
Fix old references to I18n.available_locales, complements 822288a8

Some places were still getting the complete list of locales after 822288a8,
now they all use the same method/variable that store the locales available.
Merge branch 'branch-v2' into issue804-bbbrails1.3.0

Conflicts:
	app/assets/javascripts/app/application/base.js.coffee
Several fixes and improvements for webconfs in spaces, refs #804

Finishing what was started by 8408dbde5d5.
Move metadata key names to global configs, refs #804
Show alert on rooms/join_options when the room is running, refs #804

Alert that the options will not take effect in the current meeting.

Also changed style for bootstrap's alerts (and started using them for the
alert that was added).
Add ability :create_meeting for rooms and btn to end meetings in spaces

Added ability so we can use `can?(:create_meeting, room)` instead of
`user.can_create_meeting?(room)`.

Also added a button to end meetings in spaces (in `spaces/:id/webconference`).

refs #804