Increase Headshot Mult. to BF2042 levels

As it stands, the HS multiplier is way too low to make it worth going for headshots. At most you save one shot to kill if you hit 3 headshots.  The Hollow Points and Synth barely help, as is they're seen as useless 90% of the time. BF2042 HS Mult was better than this. Make aim matter again.