Correctly cast SimpleUUID::UUID
Test legacy schema support in separate appraisal

A couple of advantages:

* We can skip that particular gemfile on Travis, where Thrift is unreliable
* Allows tests to be run in a CassandraCQL-free environment to make sure there
  aren't any left over accidental dependencies on it
Add pry to Gemfile for local debugging
Merge pull request #83 from outoftime/simple-uuid

Cast `SimpleUUID::UUID` to `Cql::Uuid`