rename some types to work around injective type family stuff

[santolucito]

this is really not the right way to address this issue probably, but it seems to work fine for now. This should fix #3 just get things working, but it seems to have some deeper issue related to/that might be fixed by https://ghc.haskell.org/trac/ghc/wiki/InjectiveTypeFamilies

[brunjlar]

It seems with your changes, the Travis CI fails with similar (symmetrical) complaints.
My suspicion is that the problem is caused by underspecified dependencies in the cabal file. I am using stack for my builds, and it works just fine.
I will try to create a new version with explicit upper and lower bounds and see whether that will get it to work for both Hackage and Travis.