small universal filament spool holder -- works also for full/new spools

Based on MrMdR's wonderful small universal filament spool holder I did a small change so that it also works when you have a new spool that holds so much filament that it might tip over since the filament touches the inner part of the rail.

For this to work you need to connect the 2 spool holders with a M4 thread rod and add nuts on each side so they're held at desired distance.