Array textures can be easily drawn without a shader (resolves issue #1111).

Added love.graphics.drawLayer(texture, layerindex, …). ‘texture’ must be an array texture.
Added SpriteBatch:add/setLayer.

Added Quad:get/setLayer. This applies to array textures that are drawn without specifying an explicit layer index in the draw call.

Added love.graphics.newQuad variants which have layer arguments.

--HG--
branch : minor

src/modules/graphics/Canvas.h

@@ -57,11 +57,9 @@ public:
 	virtual int getRequestedMSAA() const = 0;
 	virtual ptrdiff_t getMSAAHandle() const = 0;
 
+	void draw(Graphics *gfx, Quad *q, const Matrix4 &t) override;
+
 	static int canvasCount;
-
-private:
-
-	void drawv(Graphics *gfx, const Matrix4 &t, const Vertex *v) override;
 	
 }; // Canvas