Added more to creature tests/class. Added health to stats
Added "zero" functionality to stats and added some methods to the creature for accessing stats
Added more tests/functionality to the creature and changed to the new Stats::zero for the modified_stats and temporary_stats
Added more test/functionality to creature for speed and health. Fixed a misspelling in the special_defense test
Extended some of the creature tests and reworded some of the others
Added a lot of health testng and functionality like damage_health and heal_health
Added initail Morsel class and tests