bullet trails commit

- implemented bullet trails! i couldn't decide what color to make them, so your ship now shoots the rainbow
- lots of visual changes/updated textures
- new "random" AI. ships can now fly to random locations on the map
- guns now shoot with a new "streaming" algorithm that spreads out burst shots over time
- more dramatic camera

- fixed a graphical bug with the "Multifire" upgrade font
- higher resolution defaults

- removed unnecessary commands in material files
- the World is a singleton
- other random code fixes/enhancements