* src/graphing.c: when drawing slopefield solutions, allow the graph
	  to leave window by a small fudge factor of 1/100 of the window size

	* gtkextra/gtkplot.c, gtkextra/gtkplot3d.c: add some sanity fixes to
	  fix crashes on tick calculations when the supplied data is less
	  than sane.  The tick calculation stuff is very evil and there are
	  still some crashes around when doing insensible things with
	  graphs.