Orphan Validation

PT Story - https://www.pivotaltracker.com/story/show/77931428

* Switched to custom `date_not_in_future` validator in orphan model and added respective specs
* Introduced factories for Orphan and Address
* Removed custom message option in date validator
* Added another validation in DateValidator to make sure the value passed in is a valid Date.
* Cleaned up specs for Date Validator