Merge branch 'release-0.10' of github.com:learningequality/ka-lite into avoid_command_infinite_loops

Conflicts:
	kalite/main/management/commands/subtitledownload.py
	kalite/main/management/commands/videodownload.py
	kalite/templates/video_download.html
Merge branch 'release-0.10.0' into avoid_command_infinite_loops
Make video downloading more robust; e.g., auto-restart after dropout.
Removed "cs" topic from the topic tree, as it is broken/mostly empty.
Merge pull request #570 from bcipolli/max_none

HOTFIX: Max on list containing None fails.
Reduce font for topic list on frontpage again slightly.
Merge pull request #568 from jamalex/remove_cs_topic

Removed "cs" topic from the topic tree, as it is broken/mostly empty.
Coolio, thanks for looking so in-depth at these things!
Fixed errors in #566
Merge pull request #567 from jamalex/avoid_command_infinite_loops

Avoid command infinite loops, and make video downloading more robust (e.g. auto-restarting)
Merge pull request #573 from dylanjbarth/subtitle_fixes_fixed

Fixed errors in subtitle downloading
Disabled retry download button while we check to see if a connection has been established.
Change the "link" to "share" in coachreport.
Merge pull request #575 from wangguan59/change_link_name

Change link name
Merge pull request #574 from dylanjbarth/disable_download_button_offline

Improving UX of retry video download button
Actually reset streak/points (and save it) when hint is taken.
Merge pull request #580 from jamalex/clear_points_on_hint

Actually reset streak/points (and save it) when hint is taken.
Only count the first click of the "hint" button as an attempt.
Don't make unnecessary /api/v1 requests from khan-exercise.js
Only count the first click of the "hint" button as an attempt.
Don't make unnecessary /api/v1 requests from khan-exercise.js