Added DuplicatedCodeDetector skeleton.
Added mass() method to find the mass (number of nodes) of a tree.
Added Method util skeleton.
Added unit test for Method class.
Added LocalVariableVisitor to find variables and parameters.
Added getLocalVariables implementation.
Added finding local variables. This is needed for the HashVisitor.
Added hashSubtrees method.
Added HashBucket skeleton.
Added unit test for HashBucket.
Implemented HashBucket.
Added Clones class skeleton.
Implemented addClonePair() method.
Implemented size() method.
Implemented getItem() method.
Added ParseTreeSimilarity class that get the similarity of parse trees.
Added getClones() method to DuplicatedCodeDetector.
Added duplicated code detection for input files.