Validation on date/date times and set the start year on date selects

Setting the start year allows people to fix wrongly set dates, otherwise rails only allows 4 .. -6 as the year.

The validations prevent future issues when the year is not selected and sets the year to 0001. Have chosen to use 1900 as the start year to allow for back dated publications, and fixed tests to be before this date.

Also made use of the validates_timeliness for closing_on after opening_on dates.

https://www.pivotaltracker.com/story/show/47806169