Fix the last edited heading in collections

Last modified time shows as 'x days ago ago' (top right in the picture).

![before the fix](https://cloud.githubusercontent.com/assets/680284/4977127/c2e92e1a-68e4-11e4-9938-7ac9208b77b8.png)

The commit also introcudes a way of running unit(?) tests for knockout.
The spec loads a mocked list of fronts, collections and items and starts the application.
The test is trivial, it just asserts the text of an element, but it can be extended in the future to run assertion on user interaction.

Tests run automatically on team city or manually with `grunt test:unit:facia-tool`.
Debugging can be done with
```
cd facia-tool/test/public/config
karma start
```
For clarity, you could delete all the switches except 'facia-tool-disable', 'facia-tool-draft-content', 'facia-tool-sparklines'