native user_slap(index, power, rnddir = 1);
Power of the slap
If set to zero the player will be slapped along it's aim
vector, otherwise the direction will be randomized
Slaps the client with specified power. Killing the client if applicable.
This removes "power" amount of health from the client, performing
a kill if they have no health left after the slap.
The function will apply a velocity to the client that is independent
of the slap power. The slap direction can be influenced by the third
1 if user is alive and slap succeeded, 0 otherwise