Fixes#1556.
* Add ImageData/CompressedImageData:setLinear and ImageData/CompressedImageData:isLinear.
The flag is used as a hint when loading a texture from the data to determine if the format should not be treated as sRGB-encoded. The 'linear' flag in newImage overrides this.
* love.graphics.readbackTexture automatically sets the linear flag on ImageData it returns when the texture's format is linear.
This allows an ImageData generated via readback to be fed back into a new Texture and the format will match the original Canvas.
* Also clean up some image decoding code.
- 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
Renamed the love.image CompressedData type to CompressedImageData.
love.math.compress returns a love.math CompressedData object which holds the newly compressed data. Currently supported formats are "lz4" and "zlib". Note that the formats are not file formats and don't compress filesystem hierarchies.
Sasha Szpakowski
Bart van Strien