SaVi satellite constellation visualizer savi-dev

Noting Mars constellation menu is for Mars.

Setting per-planet default color shades.

So far, there is only Earth (default yellow to red and blue)
and Mars (whitish to gray, and red).

SaVi color shades in the menu now sets depending on what
the planet is.

Need to indicate in windows (main/coverage/fisheye)
what planet is being simulated.

Supporting changing menus between different bodies,
so that we can offer different simulations for each
planet/moon. (The Clarke stationary script will see
reuse, but its comments would need tweaking, at least.)

Constellations menu is used in main/coverage/fisheye.
Locations menu is just used in fisheye.

Fixing menu typo: Med. Sean -> Sea

Updating note on simulating Mars/other bodies.

upating savi constants dialog to show new formatting, Earth/Mars popup.

Introducing planetary body C-side. Earth is 0, for now Mars is 1.

Also removing 'savi' command, which was duplicate of 'satellites', never used.

savi command as an alternative to satellites was never used. Shorter, though.

Reset to default now obeys planet setting.

there's a lot of cruft C-side around defaults.

Minor cleanup of display variables - they're an overlay params_display().