Update the URL to the new android mobile client
First changes for the new logic when joining via mobile

There will be a single button to join a conference. If the user is in a mobile
device, the mobile client will be automatically triggered. The old modal window
to join via mobile was removed.

Made a new "mobile" layout, currently only used in the page shown to join a
conference from a mobile client, but that can be used for more in the future.
Update bigbluebutton_rails and automatically join via the mobile app

refs #1247
Use an icon to identify the dropdown button with webconf options
Remove device options from the invite view

Now there's no need to selected if joining from a mobile or desktop, since
the join action will do it automatically.
So the invite view now only confirms the user name and asks for a password
(for private rooms).

refs #1247
Update mweb_events, fix ordering of events

refs #1159
Improve a few output messages in db:populate
Merge branch 'branch-v2' into branch-v2-mobile

Conflicts:
	Gemfile
	Gemfile.lock
	app/assets/stylesheets/app/application/base.css.scss
	app/helpers/custom_bigbluebutton_rooms_helper.rb
Fix Space#upcoming_events after 07c5120a22b

refs #1159
Merge remote-tracking branch 'origin/branch-v2-mobile' into branch-v2
bigbluebutton_rails back to branch master
Improve migration of new attachs when attachs have no title set

refs #454
Update bigbluebutton_rails with changes to the join process

The action 'auth' was removed and now only 'join' is used to join meetings.
Have yet to finish it in the gem and check if the permissions for 'join' are
ok in the app.
Update bigbluebutton_rails and few improvements in the join via mobile

refs #1247
Fix failing tests after last update of bigbluebutton_rails

After 85a110ccb96b973555d186351e57e77c8eb9b190
Merge branch 'branch-v2' into bug1252
Show the comment written by the introducer in join_requests/show

refs #1252