Refactor: GraphNode

src/main/java/tfm/arcs/Arc.java

src/main/java/tfm/exec/GraphLog.java

src/main/java/tfm/exec/Main.java

src/main/java/tfm/graphs/CFGGraph.java

src/main/java/tfm/graphs/Graph.java

src/main/java/tfm/graphs/PDGGraph.java

src/main/java/tfm/graphs/SDGGraph.java

src/main/java/tfm/nodes/AuxiliarSDGNode.java

src/main/java/tfm/nodes/CFGNode.java

src/main/java/tfm/nodes/GraphNode.java

src/main/java/tfm/nodes/MethodCallNode.java

src/main/java/tfm/nodes/PDGNode.java

src/main/java/tfm/nodes/SDGNode.java

src/main/java/tfm/slicing/LineNumberCriterion.java

src/main/java/tfm/slicing/SlicingCriterion.java

src/main/java/tfm/utils/NodeNotFoundException.java

src/main/java/tfm/utils/Utils.java

src/main/java/tfm/variables/VariableExtractor.java

src/main/java/tfm/visitors/CFGVisitor.java

src/main/java/tfm/visitors/ControlDependencyVisitor.java