Improve creation of user on shibboleth login and more tests

Just reorganized a bit the way it is done, but it still has the same results.
Run 3 resque workers by default instead of 1
Fixing more possible exceptions in workers and renaming some of them

Objects used by the workers are not always 100% complete when the worker
is running, so we have to check this cases and just print log messages instead
of breaking the worker.
One example is when a user invites someone to join a space but removes the
invitation before the worker runs. When the worker runs, the invitation will
have no associated join request.

Also renamed the workers to make it more clear what they do. Workers with
"Sender" are the ones that actually send notifications. The others are the
ones that go through a list of objects and schedule a sender for each.
Use current_site instead of Site.current on controllers and views
Change mweb_events routes to use better names
Refactor some bbb rails abilities
Refactor web invitations
Correct space users view title

Conflicts:
	app/views/users/index.html.haml
Modified the field "user email" to read only on edit profile screen

Refs #1234
Make a few tests more generic to work on other forks
Improve how join requests are shown, accepted and declined

The view that shows a join request is now more complete and treats all
possible cases in more detail (invitation, request, who requested, etc).

Several changes in the controller to use the actions 'accept' and 'decline'
instead of 'update'. These are more specific actions and with them the code
is cleaner and we can restrict more the attributes the users need access to.

Also reviewed the recent activity items being created (partly 42e7173bce150,
that's not integrated yet).

refs #1310
Create join requests activity with valid data + some tests refs #1395
Use constants for join request types and better functions to check it

refs #1310
Better param handling for join requests

Allow users to set a role when accepting a request, but only for a few cases.

refs #1310
Send email to introducer when invite is rejected. refs #1402
Merge remote-tracking branch 'origin/joinrequest-corrections' into 1310-admins-accepting-join-requests

Conflicts:
	app/controllers/join_requests_controller.rb
	spec/controllers/join_requests_controller_spec.rb
More tests for recent activities on declined join requests

refs #1402
More consistent view and actions to accept/decline join requests

The show view is now considering all possible cases and showing the
appropriate texts/links for each.
Also improved some checks and redirects in the controller that were not
100%.

refs #1310
Proper error when a user has no permission to show a join request

Was trigerring a redirect loop. Not raises a RecordNotFound.

refs #1310
Add several integration tests for join requests

refs #1310