Different file types are now treated differently - the ObjectFiles
have different skins depending on file type of the head rev, and
non-text revisions will not attempt to display their contents when
expanded.
Possible bug: old-style filetypes might be detected wrong (ie "ktext"
instead of "text+k"). I'd have to put in some pretty complex logic to
make it completely foolproof and backwards-compatible. Right now it just errs
on the side of thinking a file is text if there's any confusion.