Fixes #199 - Canceling edits should revert change on edit Asset view
Fixes #201 - Makes assets move to proper Active/Inactive section when toggled
Update unit tests to all tests pass.
Implement correct logic for is_active

Add is_active, backup, rollback methods to Asset model
Merge branch 'Update-Unit-Tests' into Fix-GH-201

Conflicts:
	static/js/screenly-ose.coffee
	static/js/screenly-ose.js
Add unit tests for new methods on Asset model
Change start and end date to be inclusive instead of exclusive in frontend and backend logic
Merge pull request #202 from richard-to/Fix-GH-201

Fixes GH-201 - Assets do not move to "Active Assets" section when toggled "On"