Move isType out of internal and make it a predicate named isSameType

[evilsoft]

The home stretch

As we come closer to feature lockdown it is time to start cleaning up, optimizing and removing all the duplication (mostly around type assertions).

This PR is the first step in that process. The old and crusty isType just would not live in the new world. So this updates that function to be able to compare types properly in one place. Also, as it is a better interface, it is time to expose it as a real predicate available to the public. So gets a new name and an introduction to the world.

In addition to this move, and cutting over all dependent files, did a couple more 💄 bits:

• Add both to Arrow and Star on the README
• Flesh out the predicate signatures on the README
• Expose some missing predicates to the public API that were missed a couple PRs ago 😧
  • isBoolean
  • isInteger
  • isMonad
  • isSetoid
  • isTraverable

[coveralls]

Coverage remained the same at 100.0% when pulling ba7b1a6 on isType-pred into 969b105 on master.

[evilsoft]