Setter and Getter test added + added @Before JUnit annotation.
Added new toString and getGcd methods as well as refactored Fraction class.
Added new get Least common multiple method and test.
Added new method add() and tested numerator and denominator underflow and overflow separately.
New method subtract() added including overflow and underflow tests.
Corrected errors in Fraction class + Refactored Fraction class + added new absValue method and tested it.