set courses_are_browsable flag to False, fix unicode error

Improve problems acceptance tests

Wait for js/base in CMS acceptance tests to ensure click handlers are installed

Disable test seen to fail on PRs

Translation overrides

installed.

Usefull variables for translation

Jarv/fix static root

Check for requeued subtasks when in RETRY state.

import: handle case where result has not responseText

Better indication of what mode is active in the wiki.

Add visual indicator to the interface for start/end times

Fixing merge conflicts in tests.

Setup leanModel handlers on jQuery.ready() so that the rest of the scripts get a chance to load before modals can be activated.

It turned out to be that when you run the tests in
cms/djangoapps/contentstore/features/video.feature
all at once, then test # 11 starts with transcripts already turned on. When you
run just the test # 11, then transcripts are not available (from previous tests).
That's why to make width consistent, we have to make sure that transcripts are
hidden.

Instead of raw comparison against an HTML string to get style information,
now proper selenium function is used to get value of CSS property.

Also moved all static styling to SCSS.

If end time is specified (which means that there is also a start time), we
add an extra DOM element to the slider that will show the are in time between
start time and end time. Unfortunately, this visual aid will become available
ony after start of playback. This is because until then we don't know the length
of the video.

Add Timed Transcripts Editor.