added UITableViewCellEditingStyleInsert iOS API as styleInsert

I'm more than happy to sign the CLA on this change. 
What this does (I'm not sure why the iOS 7 code is there. that isn't part of my intended change) is bring the iOS tableview UITableViewCellEditingStyleInsert API into titanium.

http://blog.codexlabs.com/blog/2013/08/31/uitableviewcelleditingstyleinsert-is-now-a-pull-request-for-titanium-mobile/

If I need to build a sample app and submit that I am more than happy too. 

To use this API one would 
do 
var tableView = Titanium.UI.createTableView({
    data: someData,
    editable: true,
    styleInsert: true,
    deleteButtonTitle: 'Delete'
});

I'm not sold on the API because if editable is false then styleInsert is ignored. However, once we (appc and the community) can agree on how the developer API should look, I am more than happy to apply this iOS API on TiUIListView.m