Library no longer supporting ruby 1.9.x

1.9.x will be deprecated in February of 2015, so there is little
incentive to write our new library to support it. 1.9.x users should
still be able to use V1 of the API.

This commit adds some changes, such as named arguments, that are
incompatible with 1.9.x.
Rakefile to clear added api keys

Local tests are run many times a day, but the Travis.CI tests are run
against test server accounts. So the default task (for Travis.CI) does
not clean up all API keys from the local server, but there is a rake
task that can be run locally or remotely to do this for you.