Implemented purchase scientists.
renamed purchaseScientist[s]
Implmented purchase laboratory; Fixed syntax error in other purchase functions; some cosmetic changes; add some getters;
merge with eldar
Merge branch 'master' of https://github.com/eldardamari/spl-assignments

* 'master' of https://github.com/eldardamari/spl-assignments:
  Statistics: toString() - finished - UNTESTED
fixing bugs in ScienceStore & ChiefScientist.
 ScienceStore():purchaseLaboratory() - Done - Untested