[DDF-815] Add Responsive IFrame Functionality to Admin UI. Added new bow...

Updated bower import to iframe-resizer 2.6.2.  Updated iframeView.handlebars to 100% width and no scrolling. Updated PluginTabContent.view.js to initiate dynamic resizing of tabs.
do we need to destroy this onClose?  also use view.$('selector') instead of the global $('selector')