Solving some bugs with the variabilization based pruning.
Merge branch 'directedmutations' of https://github.com/zeminlu/comitaco into directedmutations

Conflicts:
	src/ar/edu/taco/stryker/api/impl/DarwinistController.java
	src/ar/edu/taco/stryker/api/impl/VariablizedSATVerdicts.java