Use Ant to get list of targets instead of XML parsing

Hi,

I hacked this together when I figured out why Super Ant wouldn't work on my Android project. Hope it is aligned with what you want out of Super Ant :)

This has the advantage of supporting buildfiles like e.g. the Android
SDK generates, where there are by default no <target> elements, and all
targets are instead defined by imports and the like.

It uses subprocess.Popen to execute Ant when gathering targets, since I
couldn't figure out how to get output from Sublime's own command
executing API.