Edit tiles

You can now edit tiles and save them back to the project file. To edit a tile select a color from the palette and fill the desired pixel in the tile image with that color.
As an example I put a circle in the yellow round sprite thing.

To write the edited tile back to the ROM I need to adapt the compression routine from Python to C# which I already started to work on.
When this is accomplished I will upload the current version of the editor.