[GooberRF]

• Improve particle handling and performance:

  • Stop simulating level-placed decorative particle emitters while they are out of view (cl_particlecull)
  • Step particles at a fixed rate (cl_particlefixedstep, cl_particlerate)
  • Test distant particles for world collision less often (cl_particlecollidelod)
  • Raise the particle pool size to 8192 (cl_particlepoolsize)
  • Raise the particle emitter limit from 128 to 8192
  • Render particles, plankton, rain and snow on the GPU with instancing, and simulate rain and snow motion on the GPU (Direct3D 11 renderer only)
  • Add dbg_particles overlay and dbg_particles_log to measure particle performance, and dbg_particlewarmup to toggle replaying a hidden particle emitter when it comes back into view

• Raise the pitch of hit sounds as consecutive hits land, toggleable with cl_hitsounds_streakpitch

• Raise the limit of simultaneously playing sounds from 64 to 127

• Fix spectate control hints overlapping the team scores in Wipeout

• Fix long key names in spectate control hints running off the left edge of the screen

Resolves #215