This function was badly named and completely undocumented. Rework it to
avoid copying the full UID list using an iterator. Make it possible to
hand it a list of UIDs as strings rather than implicitely relying on the
fact that they are numeric already. Document the code.
The behavior off the function itself remained otherwise unchanged.
Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>