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
The use of `Date.today` necessitated a bug fix a couple of weeks ago. `.today` is a Ruby method that gets the time from the OS and is ignorant of the timezone of the Rails app. Tests were failing for me locally between midnight and 3am because they used `.yesterday`, which is based on `.current` and is therefore timezone-aware