correctly make use of data coming in from the event

Enyo-DCO-1.1-Signed-Off-By: Cole Davis (cole.davis@lge.com)
update the same as modelsAdded method

Enyo-DCO-1.1-Signed-Off-By: Cole Davis (cole.davis@lge.com)
fix errant logic and ensure that buffer is resized properly even if models being added are after the edge of the current pages and simplify logic in modelsRemoved to better handle its special case

Enyo-DCO-1.1-Signed-Off-By: Cole Davis (cole.davis@lge.com)
Merge pull request #742 from enyojs/BHV-9437-coledavis

Fix for: BHV-9437