Merge pull request #31 from jacosro/organize-nodetypes

src/main/java/tfm/graphs/augmented/ACFG.java

src/main/java/tfm/graphs/augmented/ACFGBuilder.java

src/main/java/tfm/graphs/cfg/CFG.java

src/main/java/tfm/graphs/cfg/CFGBuilder.java

src/main/java/tfm/graphs/pdg/ControlDependencyBuilder.java

src/main/java/tfm/graphs/pdg/PDGBuilder.java

src/main/java/tfm/graphs/sdg/MethodCallReplacerVisitor.java

src/main/java/tfm/nodes/type/NodeType.java

src/test/java/tfm/graphs/pdg/HandCraftedGraphs.java

src/test/java/tfm/graphs/pdg/PDGTests.java