First pass at TTC support, now with rewards!

FYI, https://github.com/google/woff2 now has support for TTC. Point
woff2_compress and woff2_decompress* at a TTC and in theory it will Just
Work.

In practice, I strongly suspect there are edge cases where it does not Just
Work. If you have a bunch of TTCs and were up for testing if they can be
compressed/decompressed that would be awesome.

In fact, I'd be prepared to ship you a Google Fonts T-Shirt** if you send
me either a TTC that doesn't work or a sufficiently detailed explanation
(pull request is ideal :D) of a problem for me to fix it.

Caveats and Disclaimers!
* woff2_decompress currently always puts the extension .ttf, regardless of
what it actually decompressed.
** Offer valid only valid if Google Shipping can reach you. One per person.
I probably can't give away more than 5-10 total. Other disclaimers as I
come up with them!