Add locations resource

Includes tests
Updated to include Client#locations

This is my first open source pull request, so please let me know if there's anything I missed!
Add locations resource

Includes tests
Updated to include Client#locations
Added example to README.mdown
This is my first open source pull request, so please let me know if there's anything I missed!
Merge pull request #21 from jmiramant/add-locations-resource

Add locations resource