append, gcc, moving/copying articles

[Simon Josefsson <jas@pdc.kth.se>]

I've added the following to the known-bugs page:

* Appending (ie `Gcc' or `B c', `B m' etc) doesn't work (yet) in the
  0.8x series.

I'll fix it asap.

(Reason: The imap library doesn't grok continuation requests)