Add Simplecov and Coveralls configuration
Add Coveralls coverage status badge to README
Update project URL in README
Set up Cane to measure code quality
Add CodeClimate code quality badge to README
Add Gemnasium dependency status badge to README
Add Client

Currently, the Client can only be configured, it doesn't do anything
else.
Lower maximum ABC complexity
Add RequestSigner class
Add Faraday RubyGem as a dependency

Downgrade Faraday to 0.8.9 to be compatible with VCR
Add VCR RubyGem as a development dependency
Add Pete::Client#connection
Add Pete::Interface::HealthCheck
Parse JSON in responses using Faraday middleware