Slightly improve IQM culling. This doesn't fix all the problems though
Relax path validation to only disallow consecutive / or .
Remove --console-log-level=warn from download-pk3-torrent.sh since debian's current aria2 version doesn't support it.
Only continue flushing stdin if data has actually been read.

Code as was would repeatedly call read() until it returned -1. However,
read() returns 0 at EOF (and I've seen this function spin because of this),
and I've read that ‘some other implementations’ may return -2.
Merge branch 'master' into for-0.26