Rename power.c to powercmd.c, and power.p to powercmd.p
Remove doturn to doturncmd
Use .h for prototypes instead of .p
Put include guards around ship.h, var.h, fire.h.  IWYU fire.h.  Remove declarations from proto.h.  Remove unneeded externs on functions in fire.h
Start splitting per-binary global variable definition into globals.h.  Put copyright in COPYING.  Use IWYU on fire.c.
Run clang-format