ChangeSources: implement the resource type in terms of the new data model

Here it is! This is modelled fairly closely to the Schedulers changes.

I've gone through all the CS classes and: 
 * add a 'name' parameter, and generate one if it's not explicitly set. These will be used to 'claim' the CS for a particular master, so it needs to be meaningful in all cases.
 * use activate/deactivate to start and stop the CS. Usually this means just changing startService/stopService to activate/deactivate