Put the rain stuff on activeObject

Part of RFC #36.

###Situation
Rain is a result of a click but the data lives seperate from all other data gathered after a click.

###Problem
In the light of RFC #36 all data is either the result of a click or an aggregation of the extent and belongs to respectively a activeObject object or extenAgg object. 

TODO:
- [ ] Rename scope.activeObject to scope.click
- [ ] Add rain to this object
- [ ] Update scope.click after every click