Add basic ortho and perspective projection APIs to love.graphics.

- Added love.graphics.setOrthoProjection.
- Added love.graphics.setPerspectiveProjection.
- Added love.graphics.resetProjection.

Note that the projection is reset whenever the canvas changes.

src/common/Matrix.h

@@ -23,6 +23,7 @@
 
 // LOVE
 #include "math.h"
+#include "Vector.h"
 
 namespace love
 {
@@ -88,6 +89,11 @@ public:
 	 **/
 	const float *getElements() const;
 
+	void setRow(int r, const Vector4 &v);
+	Vector4 getRow(int r) const;
+
+	void setColumn(int c, const Vector4 &v);
+	Vector4 getColumn(int c) const;
 	/**
 	 * Resets this Matrix to the identity matrix.
 	 **/
@@ -222,6 +228,11 @@ public:
 	 **/
 	static Matrix4 ortho(float left, float right, float bottom, float top, float near, float far);
 
+	/**
+	 * Creates a new perspective projection matrix.
+	 **/
+	static Matrix4 perspective(float verticalfov, float aspect, float near, float far);
+
 private:
 
 	/**