Update the development gem dependency version requirements
Test against Ruby 2.1

…and head Ruby.
Use Bundler to execute the Travis build script
Remove explicit declaration of default gem require path
Test against Rails 4.1
Swap out Coveralls for Code Climate test coverage tracking
Update the RSpec version requirement
Update the Aruba version requirement
Update the readme badges

[ci skip]
Update the readme and add contribution guidelines

[ci skip]
Correct the license attribution

[ci skip]
Add a changelog

[ci skip]