Log Message:
Update ruby-mocha to 0.13.2.

# Release Notes

## 0.13.2
* Stubbing of methods re-declared with different visibilty. Fixes #109.
* Add `Mock#responds_like_instance_of`. Fixes #119.
* Make `Expectation#inspect` less verbose and more useful. Fixes #122.
* Make unit tests more robust to changes in environment. Fixes #121.
* Update README in an attempt to head Rails-related issues off at the pass.
* Add a Gem Badge to provide a link to Mocha on Rubygems.
* Make documentation example consistent with other examples.