Switch to datastax driver

### 0.2.0 / 2014-10-15

* Enhancements
  * Refactored code base to use the official ('cassandra-driver', '~> 1.0.0.beta.3') [DataStax C* driver](https://rubygems.org/gems/cassandra-driver)
  * Codebase remains backwards compatible
  * Should support new features available via the new driver (authentication, server/client certs, compression and other connection params). See [driver docs](http://datastax.github.io/ruby-driver/api/)
  * Updated to the latest version of RSpec (3.1.0)
  * Updated other development dependencies (bundler, simplecov, coveralls)