Syntax: PLanets [<keywords>]
List location and number of builds for all known planets, and a
summary of planets within a specified range or the entire
galaxy. The default range is 10 sectors, and the default side
is every side. See the help for LIST for more information and
the complete set of keywords that can be used to modify PLANETS
output.
Examples:
PL List all planets within 10 sectors.
PL SUM Give summary of all planets in game.
PL ALL NEU List all known neutral planets.
PL ALL CAP List all known captured planets.
PL ALL 20 List all known planets within a radius of 20
sectors.