Implemented autosave
Fixed a bug in which whitespace was added to saved responses on page reload.
Separate errors.py into errors/self.py and errors/peer.py

Move self_api.py and peer_api.py into an api subpackage

Split serializers.py into serializers/base.py and serializers/peer.py
Merge pull request #319 from edx/will/assessment-package-refactor-2

Assessment app restructure (part 2)
Merge pull request #313 from edx/will/autosave

Implemented autosave
Adding the ability to review a single student as staff