Color chooser and brush settings

The tile painter is progressing and I finally went through a first implementation of a color chooser and the brush settings. It's certainly not the most user friendly interface but it does its job for a first release.

The brush is previewed with the current color (while a bit zoomed for clarity). On the side of the brush preview 2 sliders allows to change the size and the "smoothness" of the brush. The smoothness of the brush is still far from being perfect but somehow works.

Still a lot needs to be done before I can consider it as the tool for the first release but slowly it's going there.

I also need to think how I want to save the images, either in the database with the advantage of having all in the database (for backups for example), or keep the images out of the DB, or having images in the DB with a static copy outside for speed.

I also wonder if I want to implement layers inside my tile maker or not. Layers are not so hard to implement and would have the advantage of offering per layer effects, however saving the image would require to keep the layer info somehow.