Updated CHANGES.txt
Added 2.7 to test
So that tests run
Merge pull request #66 from snowplow/feature/0.2.0

Feature/0.2.0
Fixed date for 0.2.0
Added TODOs for feature/0.3.0
Added currency parameter to ecommerce tracking methods (#62)
Added event_vendor as argument to track_unstruct_event (#54)
Added support for custom context to all track() methods (#38)
Added classifiers to setup.py (#48)
Added config option to disable contracts (#61)
Updated Tracker constructor to use map of optional args (#37)
Attempting to have Travis run all tests
Passed --exe option to nose in .travis.yml
Renamed duplicate test and added "pip install nose" to .travis.yml
Updated .travis.yml to use Coveralls (#64)
Added Coveralls code coverage button to README and after_script command to travis.yml (#64)
Created new add_transaction function to track a transaction and its items at once and give them the same id and timestamp (#25)
Integration tests no longer rely on the return value of the tracker methods (#65)
Changed the return value of the tracking methods to a tuple (#65)