major refactoring to datasets and Generators

Datasets now use _ to mark it as a feature.
Generator now uses class name to select features

moon and planet code greatly simplified by feature refactoring
mapdata moved to planet class from WorldMap
moisture now being tracked but not used
moon orbits are no longer generated but set, as are moon orbit speeds. Still room for improvement
specular map readded
bump map increased a bit

templates cleaned up to use new feature format
reimport now does flushall
starsystem now used to generate maps