Fix CI

[chrisburr]

I've created some new conda packages for ROOT. They're still experimental as they're dependent on the new compiler infrastructure in Anaconda 5, see scikit-hep/uproot3#183 for more details.

This should fix the build again, though it does drop testing against Python 3.4 and ROOT 5.

[coveralls]

Coverage remained the same at 100.0% when pulling 4302809 on chrisburr:fix-ci into 23cfb94 on scikit-hep:master.

[coveralls]

Coverage remained the same at 100.0% when pulling 4302809 on chrisburr:fix-ci into 23cfb94 on scikit-hep:master.

[kratsg]

Thanks, this is excellent!