[sugar] Display Use Help for better Readability in Backlight on mode

[Mary Lou Jepsen]

Readability of the display and the compromises I made in the design

The key to getting the cost down in the display was giving every single
pixel both luminance (black and white and grey) and chrominance (a single
color , red or green or blue) information.  

The luminance resolution is 3X the chrominance resolution.  Luminance is
1200x900 or 200 dpi, chrominance is ~800x600 or 133 dpi.  

Recommendation: use luminance for small fonts, and color for bigger fonts.
This will make your eyes much happier!

In addition: black pixels are higher resolution than white pixels.  That may
sound absurd - but think about it for a moment.  Each pixel also has a color
part - and with that color part -  red or green or blue information -
together red and green and blue make white with the color part of the pixel.
The absence of color (black) just takes one pixel (no red = black; no green
= black and no blue = black).  

Recommendation:  For fine text use Black on White background for best
readability.

I hope these help.  I will write more and post somewhere prominent on the
wiki with more style guidelines and recommendations.

- Mary Lou