[Devel] split_conic and split_cubic are duplicated

[Graham Asher]

Another observation arising from my work with ftgrays.c: the routines 
split_conic and split_cubic are duplicates of
Split_Conic and Split_Cubic in ftraster.c. These functions should be moved 
to a utilities module somewhere; we really shouldn't have duplicates in 
FreeType, because many users have litle memory available.

Although one set of functions takes TPoint and the other FT_Vector, that 
distinction can also be abolished; the two types are identical.

Graham Asher