Explicitly test the creation and deletion of every component type

The testing of all settings/text editing have been done elsewhere and should be done when testing a new component
Cleaned up code
Teach rake test_$lib to understand specific test names
Broke up long line into smaller line
Show a confirmation on asset delete. Fixes STUD-375.
Handle edge case when trying to aggregate progress in an empty sequence
Make url matching regex flexible to allow for browsers that munged :// into :/
Fix SessionKeyValueStore.has to use the correct indexing value when looking up data
Retrieve location from self in CustomTagDescriptor
Make request.POST be only json content when using expect_json
Standardize on get_default_time_display
Add JSON encoder for datetimes to xml export

During policy export, we want to write any python datetime objects found
as iso timestamps, rather than throwing exceptions.
Change deleted Alert to a Notification, with a timeout.
Add some documentation around XModule/XModuleDescriptor initialization.
Pylint cleanup.
Working prototype of crowdsourced hinting module.

Conflicts:
	common/static/coffee/src/logger.coffee
Began work on instructor view to hinting system.
Added moderation feature - you can now choose to hold all hints for moderator approval before showing.
Finished prototype of hint moderation view.  Began re-writing tests of the crowdsource hinter module.  (Old tests no longer cover all the code, now that moderation has been added.)
Made tests of the crowdsource hinter module more standardized and easier to read.  Fixed database non-initialization bug in crowdsource hinter module.
Fixed epic git rebase meltdown.  No new features.