Bump edx-submissions to v0.0.6

This is required following our update to a new version of ORA2.
Requirements updates for Track Changes

* Manually update ORA2 version to the TrackChanges SHA1
** Note this should be reverted when the TrackChanges PR merges upstream
* Includes submissions dependency bump to 0.0.7
Merge branch 'rc' into release

* Release 2014-08-22, picked up:
** Requirements updates for TrackChanges
** edx-submissions version bump
** help center link is a visible button
Merge branch 'release'

Conflicts:
	requirements/edx/base.txt