Handle RangeError in Rails 4.2 for allow_value / validate_numericality_of

[mcmire]

For validate_numericality_of if you use one less than the allowable max value of the column then you'll get an exception and not a failure. Related, if you use allow_value with a value that's outside the allowable max value of the column you'll get an exception and not a failure.

(Related to #634)

[mcmire]

Closed by #642