First version of color_mix et color_mix_light
color_mix, added missing includes
color_mix, minor layout adjustment

- made the background image use PreserveAspectCrop
- made the text message 'Match the color' layout adjusted
Automatic resizing
Better rendering for tube and flashlight
Remove useless files
Camel case
Re
Merge branch 'color'
color_mix, many grahical improvements

- better sizing and centering of the tubes
- new backgrounds from opencliparts
- added a brush at the tubes end to show the current color
  instead of the rectangles