ENYO-36: Add the ability to specify controlsPerPage in a DataList.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>
ENYO-36: Add documentation for new property, consolidate logic.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>
Merge pull request #812 from branch 'ENYO-36-aarontam'