Change GitHub raw file URL

GitHub issues a 301 Moved Permanently response on all calls to
`https://raw.github.com`, which redirects to
`https://raw.githubusercontent.com`.
Bump relx version to 1.0.2
Merge branch 'master' of git://github.com/kolorahl/erlang.mk
Merge branch 'master' of git://github.com/kiela/erlang.mk