Bugfix: dictionary now returns null if key not found instead of
arbitrary int value
Remove hierarchy heights
Merge remote-tracking branch 'upstream/master' into heurakles

Conflicts:
	src/main/org/deidentifier/arx/ARXAnonymizer.java
	src/main/org/deidentifier/arx/algorithm/FLASHStrategy.java
	src/main/org/deidentifier/arx/framework/check/NodeChecker.java
	src/main/org/deidentifier/arx/framework/lattice/Lattice.java
	src/main/org/deidentifier/arx/framework/lattice/LatticeBuilder.java