Fix bug when a threaded environment

Setting a default config (used by Config.reset) instead of an empty
hash seems to fix a bug when in a threaded environment (ie. rubinius +
puma).
Wrap calls to .deep_dup in a .default_config method
Merge pull request #66 from StudioMelipone/develop

Fix bug when in a threaded environment
updating some dependencies, loosening the txinfo version so that we can float between ActiveSupport versions, letting its dependency control which one we use.  Closes #67 Closes #69
Merge branch 'master' into develop
bumping to version 0.7.1
bumping my dependency on myself
Extend ActiveSupport::TimeWithZone the same way we extend Time