Added Transform objects to love.math (resolves issue #1228).

- Added love.math.newTransform.
- Added love.graphics.applyTransform and love.graphics.replaceTransform.
- love.graphics.draw/print/printf, Text:add/addf, and SpriteBatch:add can accept a Transform argument.
- love.graphics.push can accept an optional Transform as a second argument, which will apply the Transform after pushing the matrix stack,
- Shader:send can accept Transform objects when sending to a mat4 uniform variable.

--HG--
branch : minor

src/common/Matrix.h

@@ -52,6 +52,12 @@ public:
 	 **/
 	Matrix4(float t00, float t10, float t01, float t11, float x, float y);
 
+	/**
+	 * Creates a new matrix from the specified elements. Be sure to pass
+	 * exactly 16 elements in!
+	 **/
+	Matrix4(const float elements[16]);
+
 	/**
 	 * Creates a new matrix set to a transformation.
 	 **/
@@ -182,6 +188,9 @@ public:
 	template <typename V>
 	void transform(V *dst, const V *src, int size) const;
 
+	/**
+	 * Computes and returns the inverse of the matrix.
+	 **/
 	Matrix4 inverse() const;
 
 	/**