prettylinks in websocket.tid
Improve drag and drop

file witht extensions like html, txt, json, atom (which are used by
the api) so do not quite work, are PUT with the extension removed.

This fixes #58

Also, when a file mime type cannot be figured out, give an error
message rather than just failing. It turns out that at least some
browsers don't do file magic when determining file.type, instead
they just looks at the extension. Weak sauce! The solutions that's
been put in place allows for browsers to get better.

And, based on a suggestion from @pads, the messge area updates to
show a link to the just uploaded file when it has been successful.