Using a recent activity object for notifications
Initial testing with task schedule and resque, message jobs
Mount resque admin with schedule addon
More emailing messages converted to recent activity + workers
Merge branch 'branch-v2' into branch-v2-refactor-emails
Adds invitation by email to events

`initializers/mweb_events.rb` now loads controlers and models from `lib/mweb_events/`

`lib/mconf/invitation.rb` is now a generic class for invitations. WebconfInvitation and EventInvitation
implement more specific stuff

refs #1216
Invite button opening modal + some translations

refs #1216
Refactor common behavior of invitations a little more

refs #1216
Update the URL to the new android mobile client
Refactor attachments

Conflicts:
	db/schema.rb
Store attachments where logos are stored
Migrate old attachments
Remove lots of dead code in attachments and library dependencies
Make multi download and remove work again for attachments, refactor controller
Removed a bunch of code from attachments controller/model
Make tests for attachments pass. They're mostly abilities tests
Remove unused gems and files
Remove unused fields from attacments
Remove many unused gems
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.