#5679 - Compute MTU inside freenet using getMTU (still needs to ignore local interfaces)
Ignore loopback adaptor when comptuing MTU
FCP message to apply the content filter to a specified file and return the result.
Remove inappropriate constructor for FilterResultMessage.
Eliminate calls to getIdentifier and isGlobal.
Either determine mime type in constructor, or fail.
Merge remote branch 'vwoodzell/filter-test' into next
Merge remote branch 'vmon/f--native-getMTU' into next
Remove finished uploads

Added a button to remove all finished uploads from the upload pane in
one go as a fix to the bug
https://bugs.freenetproject.org/view.php?id=1969
Tidy up slightly, only show for finished uploads.