Misuse of 'gettext' into mako templates

To translate strings in mako templates, the pattern of ```${_()}``` should be used instead of ```gettext``` even if the strings to be translated is located in a ```script``` block.
Merge pull request #4282 from louyihua/fix-name-in-studio

Misuse of 'gettext' in mako templates
Refactor global var setup for forum Jasmine tests

Originally reviewed in #4072
Re-design forum thread list

Use larger and lighter title font, decrease padding, and use lighter
solid backgrounds instead of gradients. Also, refactor SASS code to
conform better to our new style, including using more specific class
names.

Originally reviewed in #4072
Add labels to forum thread list

A thread will be labeled if it is pinned, if the user is following it,
or if it was authored by a staff member or community TA. This also
slightly changes the color used for community TA labels.

Originally reviewed in #4072
Make "load more" in forums not appear incorrectly

The rendering of the link happens in an event handler, and the
collection's attributes were not getting set properly before the reset
event triggering the rendering occurred.

Originally reviewed in #4072
Improve forum sorting and cohort filtering UX

Thread entries now show an activity count that includes the original
post, and only one of the vote count and activity count is displayed
based on the user's selected sort. The sorting and filtering options now
both use a select and are somewhat more verbose, and the visual styling
of the sort/filter bar is updated.

Originally reviewed in #4165 with a bugfix in #4211
Update discussion tab sidebar header

The home button is removed, the search box is always displayed, and many
visual adjustments are made, along with a large amount of refactoring.

Originally reviewed in #4211
Adds subtree_edited_on, subtree_edited_by, and fixes has_changes
Merge pull request #4291 from edx/forum-sidebar-improvements

Forum sidebar improvements
Merge pull request #4273 from edx/benmcmorran/subtree-edited-info

Adds subtree_edited_on, subtree_edited_by, and fixes has_changes
Missing "_()" in course_module.py
Make the strings in "Advanced Settings" page localizable

The fields should be translated before render into html templates.
Merge pull request #4286 from louyihua/studio-advanced-settings-localization

Make the strings in "Advanced Settings" page localizable
Merge pull request #4287 from louyihua/localization-cms

Missing "_()" in course_module.py
Fixes has_changes to search all the way to leaf nodes
skipping update assets, not just collectstatic, in unit tests
Add openedx-analytics discussion group to CONTRIBUTING file
Update AUTHORS
Merge pull request #4299 from edx/clytwynec/skip_update_assets_for_unittests

skipping update assets, not just collectstatic, in unit tests