KrancThorn.m: Move coordinates code processing to a separate function
KrancThorn.m: Move inheritance of grid into coordinates function
KrancThorn.m: Move CactusBoundary code processing to CactusBoundary.m
Move Boundary inherited implementations into CactusBoundary.m
KrancThorn.m: Collect GenericFD-related code into a single function

Changes ordering of inherited implementations in interface.ccl.
CodeGenInterface.m: Sort various items in interface.ccl

This should make the generated code less sensitive to internal restructuring in Kranc.
KrancThorn.m: Move groups check to start of function
KrancThorn.m: Move coordinates processing call earlier in CreateKrancThorn
KrancThorn.m: Move input parameter checking earlier in CreateKrancThorn
Move Jacobian checking call from KrancThorn.m to Jacobian.m
KrancThorn.m: Small code rearrangement
Move symmetries code processing from KrancThorn.m into CodeGenSymmetries.m
KrancThorn.m: Move calculation splitting call to separate function
KrancThorn.m: Move option distribution code to its own function
KrancThorn.m: Move ODE code processing into a separate function
KrancThorn.m: Move DeclaredGroups code processing to its own function