Add Dynamic Attributes to Page Container DIV

[signalpoint]

Right now the page.tpl.html file needs to be structured like this:

<div id="{:drupalgap_page_id:}" data-role="page" class="{:drupalgap_page_class:}">
  <!-- ... -->
</div>

This means we're stuck with id, data-role and class as the only attributes we can attach to the page. Adjust the page.tpl.html file requirements to be:

<div {:drupalgap_page_attributes:}>
  <!-- ... -->
</div>

This will allow hook_menu() items (and any custom module menu link alterations via hook_deviceready()) to place any attributes they want onto the page container div.