Merge pull request #1 from nwwatson/master

Created and tested activity model, started building helpers
Merge pull request #2 from nwwatson/master

completed helpers, fixed integration issues with attributable
Merge pull request #3 from nwwatson/master

some updates to naming conventions and testing.
Merge pull request #4 from nwwatson/master

updates to fix a few bugs