Making mocking callable objects easier

* Fixes #39
* Variables that point to callables can be mocked
* Variables that point to class methods can be mocked
* Variables that point to instance methods can be mocked
* Decorated functions that return callables can be mocked
* Decorated Functions can be mocked
Merge pull request #48 from uber/tws-fix-top-level-callable

Making mocking callable objects easier
bump version to 1.0.2
create skelaton
add faqs