CORE - refactoring, polishing, preparing for implementing optimalization stuff
CORE - improved interval multimap handling of conflicts numbers
CORE - added preferences definition, refactored solver state object
CORE - fixed occurrence cost definition
CORE - initial incomplete search experiment
CORE - merged auxilliary changes from incomplete-search
CORE - reverted compleat nonfeasible search.
Merge branch 'incomplete-search2'

Conflicts:
	core/src/net/personaltt/main/Benchmark.java
	core/src/net/personaltt/solver/core/Solver.java
CORE - improved non conflict search.