Added dimension constraint methods and functions
Added activation/deactivation functions
Documentation refactor
Made dimension and aspect ratio methods/functions return the constraint(s) they apply
Made alignment functions return the constraint(s) they apply
Fixed dimension constraints bug
Made distribution functions return the constraints they apply
Refactored some internal methods to avoid cluttering the public interface
Merge pull request #6 from samodom/dev

Added dimension/aspect ratio, activation/deactivation and added lots of returns for constraint methods/functions