Projectiles, slightly improved once more

I’ve added in some more projectiles using the new system, and added in a fragmenting, shotgun-style effect.  The player starts with seven weapons now, bound to keys 1-7.  1-3 are the same as always, 4 homes, 5 is a spread, 6 is a homing spread, 7 is a high speed homing spread which explodes into a shockwave.  All made purely by editing that projectiles.xml file.
Also added: a graph on the bottom showing the number of milliseconds per tick.  A bit more informative than just FPS, it lets you know if there’s one particular tick of the game that’s taking a long time.  A single, one-frame spike would be hard to see in a conventional FPS display, since it’s a rolling average.
Next up: Implementing the “trails” option, to give projectiles optional trails like all the ships have.  Then probably more work on the UI.

ver20