Rename "navigation.sunup" to "navigation.solar".

Build clean to reset all links. This allows adding "navigation.lunar"
to support Moontrac.
Mostly finished moontrac and navigation.lunar packages

A big "TODO" in moontrac because the "visibility" calculation is
opaque. Will leave this for someone else to finish properly.
Add latlong program.

This supports a kind of database of place names and latitudes and
longitudes.