Merge branch 'master' into next
Update French translation.
Set known flag correctly when finding new posts and replies.
Do not allow creation of empty posts and replies.

This should fix #304.
Catch all exceptions when processing an FCP command.
Catch all exceptions when processing AJAX requests.
Use named thread factory to create downloader threads.
Download updates via the thread factory, too.
Fix URL for external links.
Rename form variable to match the style of all other variables.
Use correct filter parameter.

Since the filter parser already expands the given values, the key/value
distinction of MatchFilter is redundant.
Merge branch 'fix-avatar-selection-309' into next
Merge remote-tracking branch 'beak/next' into next
Fix unit test failure.
Encode URLs correctly when creating an external link.
Add scheme to LinkType.
Check for a link consisting only of the scheme, because that’s not a link.
Add test for empty link bug.
Rename getReply() to getPostReply(), remove convenience method.
Add post reply provider interface.