Add new Object package

Currently performs no error checking, but this can be added later. The plan is to also add a schema for each class.
Code.m: Add new Code package

Objects of this class will represent a Kranc code.
KrancThorn.m: Start using Code object to group variables in CreateKrancThorn
KrancThorn.m: Continue using Code object to group variables in CreateKrancThorn
Add ApplyToObjectField to Object.m
KrancThorn.m: Continue using Code object to group variables in CreateKrancThorn
KrancThorn.m: Finish using Code object to group variables in CreateKrancThorn
KrancThorn.m: Eliminate most temporary variables in CreateKrancThorn
KrancThorn.m: Correct typo
Move CaKernel code processing from KrancThorn.m to CaKernel.m
Move MoL code processing from KrancThorn.m to MoL.m
Move differencing code processing from KrancThorn.m to Differencing.m
Move parameter checking code processing from KrancThorn.m to ParamCheck.m
Move conservation calculation code processing from KrancThorn.m to ConservationCalculation.m