[TIMOB-17893] Support data binding for TabbedBar

Allow:

<TabbedBar class="buttonBar" platform="ios" visible="{controlVisible}" prefId="{id}" index="{selectedButton}" onClick="buttonBarClick">

problem discovered when traversing a parent TableView collection and creating multiple TabbedBars, full issue detail with example code / environment details can be found here: http://developer.appcelerator.com/question/178619/bug-in-alloy-tabbedbar-when-using-datacollection#answer-283287 N.B. to be able to assign in the view

id="{id}"

would also be really helpful.