feature collection cleanup

Remove references to deprecated feature collection methods, that are now removed from GeoTools.

* Remove CollectionListener methods (addListener, removeListener)
* Remove Iterator Methods (iterator, close, purge)
* Remove Collection Methods (add,adAll,clear,remove,removeAll,retainAll)

For more information see https://github.com/geotools/geotools/pull/44

The cleanup went smoothly for uDig ... except for TableView.

Had to migrate from FeatureCollection/CollectionListener methods (which are gone) to FeatureSource/FeatureListener methods. This may mean we need to ask TableView to latch onto a FeatureSource now 

So testing is needed