mu4e-utils: Detect if update process asks for a password.

Offlineimap (or other mail fetchers) may query the user for a
password. This patch adds a process filter to the `mu4e-update-mail'
process and checks if the process asks for a password (Currently only
matches "^Remote: Enter password: $"). It then reads the password from
the user.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
mu4e-utils: Moved process filter and password regexp to own function/variable.

The process filter is now `mu4e~process-filter' instead of a lambda
function and the regexp is now a variable
`mu4e~get-mail-password-regexp'.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
* mu4e: add `mu4e~get-dirs', to speed up getting a list of maildirs
mu4e-utils: Password query string as variable.

Added `mu4e~get-mail-ask-password' instead of a simply "Password: "
prompt.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
* mu4e-view: fix mu4e-view-wrap-lines, mu4e-view-hide-cited
* mu4e: much faster mu4e-get-maildirs
* mu4e: always put images (inline or attachment) in the list of attachments
Merge pull request #53 from ruediger/passwd

* mu4e-utils: detect if update process asks for a password, and let user provide it
mu4e-utils: Only ask for pwd if the update process is called interactively.

Adds a new optional parameter INTERACTIVE to `mu4e-update-mail' which
is passed as a process property (`process-put') to the filter
function.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
mu4e-utils: In process filter detect if buffer is nil.

If `mu4e-update-mail' is called with BUF set to nil then the messages
should be discarded.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
* mu4e: experimental support for fancy (non-ascii) characters for flags and
  thread prefixes. Based on idea by Niv Sardi (xaiki)
* cosmetic
* mu4e: use defsubst for mu4e~proc-eat-sexp-from-buf
Merge pull request #56 from ruediger/passwd

* mu4e: ask for password only when used interactively, detect if buffer is nil
* mu4e: set mu4e-get-mail-command to "true" (default), so it will still work
  even if users don't have an actual get-mail command.
* mu4e: workaround (hack) for org-mu4e bytecompilation (don't require org-exp)
* configure.ac: tighten checks for f17; bump version to 0.9.9-dev4
* mu4e: s/mu4e-headers-use-fancy-chars/mu4e-use-fancy-chars/ and use it for
  the arrows in header mode as well
* mu4e-utils: minor
* TODO: update