[tex-live] GitHub mirror/Travis-CI

[Joseph Wright]

Hello all,

A note of thanks to the TeX Live team for the new(ish) mirror of TL 
sources available on GitHub 
(https://github.com/TeX-Live/texlive-source), and the Travis-CI 
integration. For a non-expert such as myself, this makes fiddling about 
with minor code changes pretty easy to test: a real boon. It's also 
great as a model for what one needs in a Linux VM for local (faster) 
building (I've been using the Ubunut-based WSL).

Joseph