Fix date time handling

* Enhancements

  * Support Elixir 1.3 Calendar types
  * Support polygon types
  * Support JSON type
  * Support unix sockets
  * Support transaction status propagation from database
  * Update to DBConnection 2.0.0

* Bug fixes
  * Fix ping error handling

Release v0.9.0-rc.0

* Enhancements
  * Support Elixir 1.3 Calendar types
  * Support polygon types
  * Support JSON type
  * Support unix sockets
  * Support transaction status propagtion from database
  * Update to DBConnection 2.0.0-rc.0

* Bug fixes
  * Fix ping error handling

Release v0.8.4 version

Release v0.8.3

Release v0.8.2

Release v0.8.1

Release v0.8.0

Release v0.7.9

Release v0.7.8