Studio: Switch class-based Sass @extend rules to use Sass placeholder syntax

Simplify static page acceptance tests

Teach rake to run all python tests as a group

make tooltips screen-readable

Adam/a11y

Tabbing through captions

edx.org/LMS: FIX - Reverts Sass placeholder extend back to view-based selector

Fixed duplicate ID attributes in registration & login

Removed unfocused class and set the captions default values of outline-width and outline-style to it.

Replaced mouseenter and mouseleave event handlers by mouseover and mouseout. The former were failing Jasmine tests. Since the captions are li elements without descendants, they are identical.

Conflicts:
	CHANGELOG.rst

Rc/2013 09 18

Valera/bugfix access to hidden controls

Fix import errors with unicode filenames

Turned off jQuery animations. Went through all of the XModule tests and
checked that all spying on window.setTimeout() function is done properly.

Hotfix/lti typo

Replace references to .system

Add rb-inotify dependency

Indicate that rb-inotify and rb-fsevent aren't actually necessary

Problem with hideControls not being called via setTimeout().

Now when controls are uatohidden and focus is on one of them, we
switch the focus to the mian Video element.

Code documented a bit.

When controls are autohidden, we make sure that speeds and volume
controls drop downs are closed.

This reverts commit acd23ad9.