mailbox aliases for mutt

I'm a big fan of 'c' to quickly switch between mail boxes but I have to admit that my few IMAP/POP accounts are hard to reach. I know there are a few workarounds to simulate aliases but I thought I'd try a less redundant solution. This small patch allows the following syntax when defining mailboxes:

  mbalias work imaps://user@mysw33thost.com/
  mbalias errors =stuff/project/errors
  mailboxes *work *errors

It also adds the '*' prefix to access the aliases, e.g. you would access the above mboxes with 'c*work' or 'c*errors'.

mutt_mbox_alias.patch

This patch fixes ticket #3245 on mutt's BTS.