imap: fixed buggy names in generated URLs

For some reason the ImapUser variable gets emptied every one mailbox that gets
parsed. This produces the generated URLs to be not consistent among them,
generating, for example, "imaps://host.com/FolderA" and then
"imaps://user@host.com/FolderB". I haven't find the root cause of the problem,
but this at least fixes the issue temporarely
  sidebar: added initial sorting support

The initial sorting support sorts the mailboxes by hierarchy/path. This is a
nice feature to have when a user, like me, uses mutt to check its imaps
accounts.

The sorting method is still fixed, but it could be extended using a new user
preference
Update mh.c

Fix for issue 22: Warnings when building
(fix for Warning A only)
01-progress-bar.patch for Gentoo

http://article.gmane.org/gmane.mail.mutt.devel/18743

Adds a "progress" color item that draws a vertical progress bar in the
last line.
Don't consider TopBuffy as someone special, sort it as all the rest
Signed-off-by: Rodrigo Javier Tobar Carrizo <rtobar@csrg.inf.utfsm.cl>
Update Italian translation
Do not use SASL for login unless AUTH=LOGIN is advertised (closes #3556)
check_charset: check for NULL before calling strtok_r (closes #3326)

Otherwise, if strtok_r cannot handle NULL an empty *charset setting will segfault
gnutls:tls_compare_certificates: check strstr for failure (closes #3547)

A malformed certificate file could cause strstr to return an unhandled NULL.
Thanks to hhorak for the proposed patch. This one is similar but avoids using
memmem for the first time (I am not sure about its portability).
Fix some spelling errors (closes #3493)
silence some style warnings
Set text_flowed after send-hook has been applied (closes #3550)
Do not use stack-allocated space for BUFFERs

It will cause mutt_buffer_* to segfault if it needs to grow the space.
Thanks to Steve Losh for discovering the issue. I have done some simple
grepping to find other cases, but some may remain.
Split mutt_buffer_new out of mutt_buffer_init.

Currently, no callers were providing a non-NULL buffer to
mutt_buffer_init, and splitting it will allow more sane semantics for
buffer allocation, initialization, and destruction in a later patch.
mutt_buffer_init: just memset the buffer (closes #3588)

This was meant to be part of the previous commit.
Add compiler and configure info to mutt -v output (closes #3537)

Makefile(.am) updated to produce conststrings.c, which contains
C strings representing:

* the compiler's own version information;
* the CFLAGS value from the Make environment
* the ./configure options

main.c is updated to print them when running 'mutt -v'.

txt2c.sh is added to produce conststrings.c. txt2c.sh uses a compiled
txt2c binary if possible, for complete fidelity to the source strings
in whatever encoding they may use.  If txt2c is not available (could
not be compiled, or was not compiled natively) it falls back on a shell
function to approximate the output using sed and tr.
make ascii_strcasecmp properly handle unequal length strings with the same prefix

closes #3601
don't perform rfc3676 space stuffing when recalling a postponed message where it has already been done.

closes #3600
list-reply documentation should mention its behavior wrt the List-Post header field.

closes #3599
additional documentation for $editor.  closes #3602