Initial implementation
The Form class now validates its constructor arguments
RangeValidator is now {Clamped,Exclusive,Inclusive}{Min,Max}Validator

This change breaks up the somewhat monstrous and enum-strewn
RangeValidator class into smaller, simpler validators. It also adds
convenience methods to Field for working with minimum and maximum
values.
Fix a comment
Add a sentence to the README
Add a basic usage example
Fix comparison direction in ClampedMaxValidator
Added MIT license