rename motif class used in fltk code to fltk_motif

rename motif class used in fltk code to fltk_motif
I forgot to build the fltk code and so my patch that added the motif derived
from the annot class, conflicted with the motif in the fltk code.

So I renamed it. darcs replace is really neat, it made dealing with that
sooo much easier.