Fix acceptance and unit tests

LMS-1296

LMS-1296

New function was added: is_css_not_present
This function works like is_css_present in that it will wait and can take in an optional argument to wait longer.  This should be used everywhere INSTEAD of not is_css_present as in the latter case, you are telling selenium to wait for the thing you don't want to be there to either be there or time out.

* Missing docstring
* Redefining name from outer scope

for common ui manipulations

Conflicts:
	lms/templates/video.html