Added overview image.
Merge branch 'master' of github.com:youtube/vitess
Added overview.
Implemented VtoccBsonBlockingChannel and integration tests.

Allows creation of driver that communicates with a vtocc instance via Bson using a BlockingChannel. Integration tests extract queries from queryservice_test.py and run them using the driver.
Merge pull request #59 from timofeyb/master

Implemented VtoccBsonBlockingChannel and integration tests.