Returns the map zones the client is inside of as a bitflag value.
If the user does not have the ability to plant (cs_get_user_plant()
returns 0) then the bitflag will not contain CS_MAPZONE_BOMBTARGET.
For a list of possible zone flags see the CS_MAPZONE_* constants.
Bitflag value of map zones
If the client index is not within the range of 1 to
MaxClients, or the client is not connected, an error will be