Fixup for src/tutorial/func.c and src/tutorial/func.source

Fixup for src/tutorial/func.c and src/tutorial/func.source

Removed char16 and replaced with an example using Point
as suggested by Tom Lane.  The dept field was changed to
the cubicle field denoting the row(x) and column(y) of
the employee's cube in the corporate jungle.  The C function
builds a 'compromise' cubicle from two suggested ones.

I'll try and up the documentation next.

Clark