Fix Github.jl dataset urls

[SebastinSanty]

The commit variable doesn't work at the moment. Anyways master branch is a viable option.

[oxinabox]

hmmm, One actually wants to pin to a particular commit. For 2 reasons

1. We want to generate for This data, not for what ever is here later -- that could change. Most stable=more good
2. Rawgit shouldn't actually support using a named branch with the http://cdn.rawgit.com. See https://rawgit.com/ (on the left). And we want to use https://cdn.rawgit.com however master is a moving target and is not really ideal.

So I think the action here is to findout why the current is not working and fix that. My bad for not picking up the tests being wrong earlier

[codecov-io]

Codecov Report

Merging #15 into master will decrease coverage by 1.82%. The diff coverage is 71.42%.

@@            Coverage Diff             @@
##           master      #15      +/-   ##
==========================================
- Coverage   96.87%   95.04%   -1.83%     
==========================================
  Files           6        6              
  Lines          96      101       +5     
==========================================
+ Hits           93       96       +3     
- Misses          3        5       +2

Impacted Files	Coverage Δ
src/GitHub.jl	89.18% <71.42%> (-4.57%)	:arrow_down:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 609d5e1...5b62ab2. Read the comment docs.

[SebastinSanty]

Any issues with merging this?

[oxinabox]

Nope no, issues, I was waiting for travis/appveyor to finish, when I approved it. And then I forgot to come and check that it passed after. Thanks for reminding me, sorry for losing track. (I wish github had a "Mark as unread")