Added dirty tracking, fixes issue 10
Merge branch 'master' of https://github.com/nasmorn/hstore_translate into rails-4
Support Rails 4.0.0.rc1

- 3.1 and 3.2 still supported.
- Some style tweaks and clarification.
Drop support for ruby 1.9.2.
Merge pull request #14 from robworley/rails-4

Rails 4.0.0.rc1