re commit: 7641959c5c31636cb9f492e76d0f0a3c8b21a82e (don't use file contents for mimetype detection)

[David Nolden]

I'm not sure about this. My problem was basically caused by
extensionless files, that have dots inside though. For example:
bla.map.1
bla.map.2
bla.map....
bla.map.50

And so on. Simply random (large) files. An extension cache might
somewhat workaround the problem here, but only under some conditions:
1. Make sure that recognized extensions are not too large (else the
extension cache might explode)
2. Consider purely numeric extensions as "no extension at all"
3. Don't try resolving the type using the file-content for files that
have no recognized extension, as those are probably random data files

I will integrate these changes now (there doesn't seem to be your
"don't resolve the mimetype if there is no extension" logic).

Greetings, David