Adding colors to palette.
Fixed bug with incorrect color input.
Control mode: drawing/color input.
Copy mode: start/stop.
Shared partially controls for Drawing and Copy mode.
Rubber band for selection rect.
Paste mode. Using cursor rect to represent selection paste rectangle.
Drawing original selection rect. Fixed selection paste cursor size.
Fixed speedshifting cursor.
Copying and pasting selected pixels.
Pixel outputtin routine. Magenta for transparent colours.
Checkerboard background for transparent pixels.
Updating screen after changed palette's color value.