Update UI strings for example-based grading
Updating unit tests
Merge pull request #439 from edx/sylvia/docs/TIM-611

Sylvia/docs/tim 611
Fix some small things in the readme
Merge pull request #441 from edx/will/fix-readme

Will/fix readme
Use cPickle instead of pickle; add additional tests
Test setup for running the full AI grading suite in Travis
Add classy AI algorithm
Improve the AI benchmark script
Provide a Django cache to AI algorithms and use it to cache deserialized classifier data.
Add AI grading requirements, including EASE
Use wheels to install AI grading requirements
Silence warnings
Use in-memory cache without pickling
Add version info to serialized classifiers (both EASE and classy)
Default AI settings and better error messages
Strip chars before processing text
Add stemming
Use cPickle if it's available (both EASE and classy)
Generate list of grammar pos for most common words in treebank.
Move EASE algorithm into its own module