Clarify License

[ralphbean]

Thanks for the awesome tool, @bartaz.

Could you clarify the license a little? Specificaly which version of GPL is impress.js available under?

If you could include a LICENSE file with the full text, that would be best.

Thanks again!

[ralphbean]

Just FYI, a package review for Fedora is blocking on this question - https://bugzilla.redhat.com/show_bug.cgi?id=951711

[ralphbean]

Hi again, @bartaz. Just pinging to see if you could provide some clarification on the license question.

[bartaz]

Sorry, I don't have much time these days for impress.js related stuff.

As mentioned in issue #225:

MIT: http://bartaz.mit-license.org/
GPL 2 or any later version.

[ralphbean]

Thanks @bartaz. Sorry I couldn't find it myself earlier.