There is now a "tags" task in gradle!
Fix typo in last commit: borked demos tags task
Copy edits to build.gradle
sxeTarget refinements.

	- sxeTarget now has a cannonical name.

	- Configurations for sxeTarget are now exported as a map of
	  canonical sxeTarget's to values for include().
Bad sxeTarget is now an IllegalStateException.
Fix PingPongGame enum typo.
Edit TODO