implements #727
added reCaptcha to register section
feat #727
Added a boolean that enables or disables reCaptcha at user's registration form.
Improve rake task mconf:stats, refs #796

Shows now a single table with stats for all models together and also
columns with the sum of values over time.
invites/invite_room to return the user id not profile id

When searching for users in InvitesController#invite_room it was returning
the id of the user's profile but it should be returning the id of the user.
Remove html tags from private messages in the home page, fixes #812

Cases that use first_words() to get just a part of a private message's title
or body now also remove all html tags from the text to prevent unclosed
tags.
fix #774
We no longer need to update the recordings list from a room when the user is not logged in.
If the user is not logged in then we only select the data from the local database, we no longer synch with lb.
The error occured because the recordings needed an auth in order to work.
Don't fetch recordings for anonymous users in spaces/recordings, refs #774

Complements 573a47199, that did the same in the view `webconferences/show.html.erb`
but didn't modify the view that shows the full list of recordings at
`spaces/recordings.html.erb` (modified in this commit).
fix #822
When we create a new space, the visibility of the room is adjusted accordingly.
Changed space edit form to redirect when changing name refs #813
Layout changes in the edition of a space's name, refs #813

Complements 0d11160a.
Merge remote-tracking branch 'origin/feat727'

Conflicts:
	config/locales/en/mconf.yml
	config/locales/pt-br/mconf.yml
Remove simple_captcha and some adjustments to recaptcha, refs #727

simple_captcha is not necessary anymore, was used in the registration only.
Also removed from SpacesController and JoinRequestsController code that
registered a new user (:shit:) and used simple_captcha.

recaptcha was not internationalized before, not it is.
Set record false with 'update_attribute'

It's more guaranteed to update the attribute 'record' than using
'update_attributes', that can fail during validation.
fix #808
problem solved, now the user that is not logged will be redirected to the join webconf segment.
Added a button to end meetings. fixes #829
Adjustments in texts and styles in the links to join webconfs

When a user is not logged he should see "enter the room" instead of "start the room".
The rest was just a few changes in the texts and style of the links.

refs #829, refs #808
Now when a user tries to access the route to send a new join request, and he is already a member, he will be redirect to the space home page.
fixes #817
Add a flash msg redirecting from join_requests/new to space/show, refs #817

Complements 5b2d2603.
Merge remote-tracking branch 'upstream/master'