Done a new feature for limit the number of users that can record in an institution

Before this feature, institutions don't had a way to limit number of users with the ability to record meetings. To do that I created a new field inside the institution database, and all functions needed to validate the quantity of users with this capability inside each institution. Now if any institution reach the limit, administrators can't set the record ability to other members until some member with the ability is removed.

Fixes #1081
Some changes to improve the functionality that limit the number of users who can record in an institution

Modified the users controller to ensure that if a record limit of an institution is full, isn't possible to let new users receive this ability.

Refs #1081
Fixed a bug related to the autocomplete of a browser

Fixed a bug that let autocomplete options, of browser, set an institution in the creation of a new user without the user consensus
Fixed a mistake related to setting the record meetings ability

After some tests was detected a problem related to this change, so to fix it was changed the idea of the condition. Now global administrators can set the record meetings ability to any user even if the limit of users who can record in a institution are over the limit.

Refs #1081
Improved UsersController#update and added some tests to it

Modified the update condition concerning the can_record variable. This was needed because the test showed some problems when a normal user try to update this variable. Added a few more tests for it. Now global administrators, institutional administrators, and normal users are tested to ensure the update was ok when modified the can_record variable.


Refs #1081
Merge branch 'Feature1081' of git://github.com/fbottin/mconf-web into fbottin-Feature1081
Adjustments for PR #2

Most important is that when an institution admin tries to allow a user to
record but the limit has been reached, it shows a clear and specific error
about it.

The rest was just a general review on names, layout and a bit of refactoring.

refs #1081