commenting out this one if statement will enable abh for mutliplayer

https://github.com/ValveSoftware/source-sdk-2013/blob/56accfdb9c4abd32ae1dc26b2e4cc87898cf4dc1/sp/src/game/shared/gamemovement.cpp#L2469

pretty easy fix really, since the code that allows abh is only run when maxplayers is 1.

just remove the if statement, but keep the code inside.

or you could add a ConVar here for bunny hopping type, 0 is no bunny hopping, 1 is abh, and the old source 2006 bunny hopping can be set to 2, and the code for the old bunny hopping is located in this same section of code in source sdk 2006.