Fix up caching, clearing and filtering, so we cache what we need and clear only what we have to when filtering

Selection still needs work.

etemplate/js/et2_dataview_controller_selection.js

@@ -152,7 +152,6 @@ var et2_dataview_selectionManager = Class.extend(
 			if (!_noDelete
 			    && this._registeredRows[_uid].state === EGW_AO_STATE_NORMAL)
 			{
-				delete this._indexMap[this._registeredRows[_uid].idx];
 				delete this._registeredRows[_uid];
 			}