Update rspec to 2.13
Adding specs for dirty-attributes
Stub persistor to load mocked object
Add deep copy strategy spec
Dirty attribute partially implemented. specs failing
Add dirty?. No dirty strategy works.
Fix dirty specs
Implement MD5 and SHA1 for dirty attributes
Set default dirty attribute strategy to for sequel store.
Merge pull request #185 from maxigit/47872535_implement_dirty_tracking

47872535 implement dirty tracking