Add torus, line, save cmd evaluation.

Add:
	src/interpreter/interpreter.c
		-Add `torus`, `line`, and `save` MDL command evaluation to
		`evaluateMDLScript()`.

	src/graphics/matrix.c
		-Modify `addEdge()` to add a triangle (ie, three points, instead of just
		two) with one negligible, short side, so that any added lines are
		rendered properly by `drawMatrix()`.

Mod:
	test/(testAddEdge -> testAddEdge.csv)
		-The file didn't follow the test files' naming convention (a ".csv"
		extension); rename it accordingly.