Specify class that could not be found in UI.

It's already in the logs but this could make it more straightforward.
Merge remote branch 'operhiem1/specific-plugin-class' into next
FCP message to apply the content filter to a specified file and return the result.
Merge branch 'master' into next
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
Increase max peers for scaling to 100
Merge commit '8f4686349476e8d62b8685c907ed412543f91b47' into stable-1443
Build 1443.
Merge remote-tracking branch 'upstream/master' into bookmarks
Forgot The Unofficial Guide to FMS so added it, also bumb Enzo's Index to
edition 4.