Added IntIntMapTest and minor improvments

Added new IntIntMapTest to compare values with radargun benchmark.

Added new methods to KeyUtils.java for Integer keys.

Added new method addOperationRemainingProbability() to OperationSelector.java to add an operation which consumes the remaining probability.

Cleanup of bash scripts: update-stabilizer makes now use of $STABILIZER_HOME if set and uses maven to determine stabilizer version.
The `addOperationRemainingProbability` was just to ease the "be sure you have a sum of 1 for all probabilities" pain. But you are right, switching to percentage may be easier for us. Nevertheless I want to have a method like `addOperationRemainingPercentage` to just fill up the remaining gap.