Decouple response and request validationt

### What is the problem / feature ?

Request and Response validation were tangled up together.  This made it really difficult to do things like validate responses from things like `ulrlib` or `curl` since neither couples their request and response the way that `requests` does.

It also made for some confusing naming conventions.

### How did it get fixed / implemented ?

Separated them in two and renamed the combination to `validate_api_call`

### How can someone test / see it ?

Docs are updated to show the new function.

*Here is a cute animal picture for your troubles...*

![cute_bear](https://cloud.githubusercontent.com/assets/824194/5058130/be470292-6c9f-11e4-8de7-4224930467a9.jpg)