Fixed a whole bunch of refactor issues

- added some license headers
- added hashCode() were missing
- fixed issues with external distances
- fixed SSR reader issues (a.o. w.r.t. external distances)
- fixed SSR Writer issues (a.o. w.r.t. external distances)
- added param MoveType to neighbourhoods
- moved stop criteria to AbstractSearch to avoid duplicate code in
search engines
- src/test/resouces: moved all files to src/test/resources
- fixed Metropolis
- fixed Local Search
- added TabuManager + tests
- fixed Tabu
- fixed both neighbourhoods (also for Tabu)
- provided unordered IntegerSubsetSolution