* app/paint_funcs.[ch]: Added an edge_lock parameter to
 	thin_region.  Split the radius parameter into xradius and yradius
 	in thin_region and fatten_region.

	* app/channel.c: fixed a bug in channel_bounds that I introduced
 	last time I tried to fix a bug in channel_bounds.  Minor
 	modifications to work with the improved thin/fatten region
 	functions.