This function can take in a part of a name or a userid and
returns the player's id or zero if it couldn't uniquely identify one
name
It only needs to have enough of the name to identify only one person. "bl" would find the userid of "blu.knight" unless there is someone like "blackbob", in which case it would return 0.
userid
To use the userid you must have # in front of it.
(You can find their userid by typing status in console...)