ToString stub
toString works
Use GCD to reduce numbers
Negative rational numbers, part 1
Negative Rationals, part 2
Throw exception if denominator is zero
Exception if denominator causes overflow.
WIP on integer overflow
Proper handling of overflows.
First version of addition (only for equal denoms)
Addition for arbitrary denominators
Addition, with proper handling of large denominators.
Equals method for Rationals
Add a randomized test for addition commutativity.