Only use byebug to debug

* Uncomment & re-bundle if you want to use it in development
* Otherwise byebug is added to the appraisal files, which is
unnecessary for CI
Require rgeo-activerecord 1.2

* Version 1.2.0 includes fixes for ActiveRecord 4.2.0
Allow only activerecord 4.0-4.1

The adapter does not currently work with activerecord 4.2.
Version 2.2.1

* Update Readme, History