remove infinite loops from management commands. remove cruft from api_views, and tweak video_download to handle the more robust videodownload logic
updating comments, debug-based Exception forcing, to complete.
Merge branch 'release-0.10' of github.com:learningequality/ka-lite into avoid_command_infinite_loops

Conflicts:
	kalite/templates/video_download.html
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.
Merge pull request #567 from jamalex/avoid_command_infinite_loops

Avoid command infinite loops, and make video downloading more robust (e.g. auto-restarting)