sandboxing; give each loaded file its own global table
move PersistentCharacters table under Character proper and out of global
give the console its own global table
Merge branch 'lua-sandbox'
add more missing imports
add thruster directional fade and quads along axis to make them decent from every angle
Merge branch 'better-thrusters'
Merge branch 'master' of https://github.com/pioneerspacesim/pioneer into tooNoisey