Refactoring: Merged factor elimination, particlefiltering in one file, respectively.

primo/decision/UtilityTable.py

primo/decision/__init__.py

primo/decision/make_decision/__init__.py

primo/reasoning/factor.py

...o/reasoning/factorelemination/EasiestFactorElimination.py

primo/reasoning/factorelemination/Factor.py

primo/reasoning/factorelemination/FactorTree.py

primo/reasoning/factorelemination/__init__.py

primo/reasoning/particlebased/__init__.py

primo/reasoning/particlefilter.py