Feature/vik/oe messages

Feature/brian/pdf js

remove empty attempts and weights from simple test course

Fix/cdodge/serializing ints as empty strings

Add more click tracking and logging to the open ended grading interface

Change test modulestore naming differentiation scheme to uuid

template name got changed. Need to reflect that on test.

Make sure temp directories are properly cleaned up so running tests does...

Feature/cdodge/metadata inheritence crawling

don't serialize weight out as an int - use a string. The code in capa-module.py expects a string and tries to convert to a float. So this impedence mismatch is causing a crash on import when importing empty strings for 'weight' or 'attempts'

- make category a data field of an input
- namespace event types
- don't try to use the track function when it doesn't exist
- generate event types if it doesn't match a pre-existing pattern

Feature/vik/check if submission allowed