Development of system-to-lua export
Further development of exporting.
Development 3
Make generated starport latitude/longitude exportable.
orbital offset in to radians in custom systems
Enable gravpoints in custom systems -- this enables custom binary stars.
Merge pull request #10 from irigi/binary-stars-in-custom-files

Enable gravpoints in custom systems -- this enables custom binary stars.
"Physical" greenhouse clamp into 0-1 interval.
OrbitOffset into radians. This makes sense with another corrections I
will post in other pull request.
Merge pull request #12 from irigi/binary-stars-in-custom-files

merge
Remove debug code, few minor corrections.
Tidal locking as it was in #1695.
Correction of tidal-lock code to absolute definition of AxisTilt and
inclination.
Comment out the export function call, the export call should be done in
some better way. Here it serves only as an example of the call.
Merge pull request #17 from irigi/original

Original
Shadow calculation methods in Camera
alter lights in ModelBody::Render when in shadow
draw shadows on TerrainBodies in shaders
calculate proportion of disc occluded during eclipse
incorporate SpaceStation atmosphere lighting in ModelBody