Alter test results

This will give members of the "edit" group for a project the ability to "alter" test results using a simple form:

![debug-3887](https://cloud.githubusercontent.com/assets/33978/4111143/ad862e72-31ff-11e4-8dca-e0562ece330e.png)

The user name is not verified in any way, so you might put in any string (e.g. adding test results for users not registered in the application)

**Note** that an event is created for this action stating that 
`user A has altered the test result for user B to "something"`

Ref #447