Draw logo using new LogoBar class

This allows the font lookup and text rendering to be done only once
instead of on every redraw.

Note that the bar and the logo itself are always drawn together, so
I put them in the same draw method.
Tweak logo colors and positioning

The "G" of "GCW" aligns with the text inside the menu labels now,
instead of with the cursor edge.

The slightly larger logo font is avoid a particularly blurry upper
edge.

The red color logo was tweaked to better match the logo bar background,
while still matching the main menu cursor as well (as in, looking
similar: it is no longer exactly the same color).
Draw buttons using anti-aliased circles

This looks a lot smoother.
Also increased the font size slightly.
If scan failed, set 'uniq' to empty

If it is undefined, the application crashes.
Corrected left edge of error message clear rectangle

It should really be computed from constants rather than hardcoded,
but that's for later.