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
This scrollToIndex call can be rather jarring if the user is scrolled to the end of the last page because it jumps the view back to the beginning of the first page which could be as many as `rowsPerPage * 2` rows away. Will open another JIRA to address.