[ALOY-1713] Alloy Alloy widgets to be used as primary element for XML view

Would be nice to be able to have a index.xml view like this:

<Alloy>
	<Widget src="test" />
</Alloy>

which uses a widget.xml like this:

<Alloy>
	<Window>
		<Label>I'm the default widget</Label>
	</Window>
</Alloy>

And then be able to do this in the main index.js controller:

$.index.open();

Currently, you will get an error: {color:#d04437}"$.index.open is not a function. (In '$.index.open()', '$.index.open' is undefined)";{color}