Bhv 11591 Prevent unnecessary refresh() to increase performance

Issue
------
Whenever user removes models from collection, `refresh()` is executed.

Cause
--------
If removing models are placed in current pages, `refresh()` should be called.
To decide it, we use `indexOf()` to get the first position of models.
However when we call `indexOf()` in VerticalDelegates,js, models are already removed from collection
So conditional statement for deciding `refresh()` makes wrong judgement.

Fix
----
Get target index before model is removed from collection.
And deliver index info with `remove` event

Enyo-DCO-1.1-Signed-off-by: David Um david.um@lge.com
Is there a need to recalc controlsPerPage here versus using `page1.end` and `page2.end`