If I wanted to write a tutorial on Spine in the futurue, would there be a problem with including just the LibGDX runtime with the end skeleton/animation files (obviously not the spine program)?

I noticed they aren't included in the demo (so people aren't actually able to try them out, and see how easy they are to use), but anyone wanting to "try it out" would probably be interested in seeing it in action.

We're working on better definitions for our licensing:
http://esotericsoftware.com/spine-purchase/
We haven't put the license on the runtimes yet, but it will be open and probably on github, so it's fine for you to post it.