Return types changed from Set to Vector.
New method added. isShortCircuit checks whether a shortcircuit operation is required given a vector of definitions.
Added a new method isShortCircuit to check whether a given set of expressions are shortcircuit.
Added a new method for replacing the boolean expression in a shortcircuit
replaceBooleanExpr completed.
Short circuit bug fixed for fft benchmark. Unncessary if statements need to be removed and code needs to be tested on other benchmarks especially mbrt.