Add matrix multiplication, diff matrix printing.

Add:
	src/matrix.c
		-add multiplyScalar() and multiplyMatrix(), which handle the
		multiplication of a matrix by both scalar values and other matrices.
		-add helper-function dotProduct(), which returns the dot products of two
		2D arrays at a given row and column.

	src/matrix.c
		-move printMatrix() to printPointMatrix(), which prints a Matrix_t with
		(x, y, z, w) formatting
		-add printMatrix(), which prints a matrix in matrix format.
Add three matrix-creation functions.

Add:
	src/matrix.c
		-add createIdentity(), createTranslation(), and createScale(), which
		create and return identity, translation, and scaling matrices
		respectively.

	src/engine.c
		-add calls to test transformation matrices.