Implement Array, Cubemap, and Volume texture types (issue #1111).

- Add love.graphics.newArrayImage, newCubeImage, and newVolumeImage.
- Add love.graphics.newCanvas(w, h, layers) and newCanvas(w, h, layers, settings). Add ‘type’ field to the settings table of newCanvas.

- Add new love.graphics.setCanvas variants: setCanvas(canvas, slice), and setCanvas(canvastable) where canvastable is in the format: {{canvas1, layer=2}, {canvas2, face=5}}

- Add Texture:getTextureType, getDepth, getLayerCount, getMipmapCount, and getFormat.

- Remove Image:getData and Image:refresh.
- Add Image:replacePixels(imagedata [, slice] [, mipmap]).

- Update Canvas:newImageData to accept a slice argument.

- Add love.image.newCubeFaces(imagedata).

--HG--
branch : minor

src/modules/graphics/opengl/Canvas.h

@@ -39,7 +39,7 @@ class Canvas final : public love::graphics::Canvas, public Volatile
 {
 public:
 
-	Canvas(int width, int height, const Settings &settings);
+	Canvas(const Settings &settings);
 	virtual ~Canvas();
 
 	// Implements Volatile.
@@ -49,9 +49,10 @@ public:
 	// Implements Texture.
 	void setFilter(const Texture::Filter &f) override;
 	bool setWrap(const Texture::Wrap &w) override;
+	bool setMipmapSharpness(float sharpness) override;
 	ptrdiff_t getHandle() const override;
 
-	love::image::ImageData *newImageData(love::image::Image *module, int x, int y, int w, int h) override;
+	love::image::ImageData *newImageData(love::image::Image *module, int slice, int x, int y, int w, int h) override;
 
 	int getMSAA() const override
 	{