implemented rocket and electro fly sounds

implemented rocket and electro fly sounds
cleaned up nearly all sound() calls to use more appropriate channels
renamed sound/weapons/missile_fly.wav to sound/weapons/rocket_fly.wav and sound/weapons/plasmahit.wav to sound/weapons/electro_impact.wav
inlined ImpactEffect code (eliminating the unnecessary function)
changed bullet richochet sounds to use PointSound rather than playing them at the player location
sorted and cleaned worldspawn precaches
implemented experimental g_antilag cvar (makes a lagged player autoaim at the enemy they clicked on, not very useful with slow weapons)
rewrote SV_PlayerPhysics (now more sane)
now does a stuffcmd to set cl_movement cvars on a client when they join
added missing file comments to bot waypoint editor code and disabled precaches of these missing files to get rid of warnings

git-svn-id: svn://svn.icculus.org/nexuiz/trunk@425 f962a42d-fe04-0410-a3ab-8c8b0445ebaa