Actually you can invoke any intent you want with the "webpage:"
action, but that probably won't be our long term way of handling it.
We should probably just have an action called "intent:".
Here's how to launch the dialer right now:
<onPress>webpage: tel:+5551234567</onPress>
or a map:
<onPress>webpage: geo:38.899533,-77.036476</onPress>