Add rect prism triangular rendering, mics cleanup.

Add:
	src/matrix.c
		-add addTriangle(), to add triangles to a matrix.
		-mod addRectangularPrism() to render a prism with triangles, as opposed
		to individual lines.
		-rename drawMatrixLines() -> drawMatrix(), because the "Lines" was
		superfluous (and besides, the engine now renders matrices with
		triangles).

	doc/shell_help.txt
		-add the latest commands that were missing from the file (add Bezier,
		add Sphere, etc.)

Fix:
	src/interpreter/interpreter.h
		-'h' for help -- in the shell -- conflicted with 'h' for hermite; remap
		help command to 'H'.
Add polygonal rendering for sphere/torus.

Add:
	src/matrix.c
		-add polygonal rendering to addSphere() and addTorus().