[ab] New bits and pieces in Lispbuilder-sdl

[Luke Crook]

I have added several graphics primitive functions to lispbuilder-sdl. The 
following are now implemented as Lisp-native functions:

- Bezier Curves (thanks to Paul Graham and OnLisp)
- Catmull-Rom Splines
- Shape functions for drawing Lines, Points and Line Strips from a list of 
POINTs.
- Various macros to allow for the following:

	  (sdl:with-bezier (:line-strip)
	    (sdl:add-vertex (sdl:point 60 40))
	    (sdl:add-vertex (sdl:point 160 10))
	    (sdl:add-vertex (sdl:point 170 150))
	    (sdl:add-vertex (sdl:point 60 150))))

	  (sdl:with-shape (:lines)
	    (sdl:add-vertex (sdl:point 60 40))
	    (sdl:add-vertex (sdl:point 160 10))
	    (sdl:add-vertex (sdl:point 170 150))
	    (sdl:add-vertex (sdl:point 60 150))))

In addition I moved most of the examples that I had converted from 
Processing.org from the lispbuilder-sdl-gfx-examples package into the 
lispbuilder-sdl-examples (apart from those that demonstrate polygons, trigons 
circles and ellipses).

Justin's simple-font code allowed me to move the metaballs example to 
lispbuilder-sdl-examples (The font is kind of hard to read though ;))

- Luke