Legacy : VGA palette about grafx2 HOT 4 CLOSED

I think everything should be normalized to a 0-255 range (and forget about the 
old
dos version) but as i already said the palette ranges and resolutions should be
handled by plugins.

Yes, we will be normalizing in the program and in the saved files, but we must 
still
be able to load the old files, and possibly save in the old format.

I'm Converting RGB components to 0-255 range.
It's easy so far, but the numeric display of R G B looks ugly until I add a new
(small) font.
(For the time being I only change the font, and keep the rest of the Palette 
screen
layout)

Actual RGB components now use the 0-255 range.
Because of screen space, RGB value had to be printed with a thinner font that I
encoded in graph.c (function Print_compteur(). IMO the Palette screen looks good
enough for Milestone 1.0
All Save/Load functions were changed accordingly.
The menu colors in gfx2.ini are still entered with the 0-63 range for 
compatibility.

It's not visible in the current program, but the palette engine now allows 
sliders of
different ranges: If you change the value of Graduations_RGB from its current 
256 to
64 or 16 or 3 (CPC!), in RGB mode the sliders will have as many graduations as
queried. You'll still be able to switch to and from HSL mode, which always has 
256
levels of detail.
If we go forward with this feature, we'll need to clamp colors to the nearest
graduation in many places: For example after loading a picture ...