.USERNAME The username of the user to modify.
.REALNAME The full name of the user.
.EMAIL The email address of the user.
.IS_ADMIN Should be 1 if the user is admin, otherwise 0.
.NOTES Extra notes about the user.

>Edits a user definition.

!
$$ johndoe "John Doe" john_doe@doe.net 0 "NOTES"
