imap: Added support for sasl login authentication

imap: Added support for sasl plain text authentication

imap: Added support for SASL based authentication mechanism detection

Added support for detecting the supported SASL authentication mechanisms
via the CAPABILITY command.

Revert changes relative to lib/*.[ch] recent renaming

This reverts renaming and usage of lib/*.h header files done
28-12-2012, reverting 2 commits:

f871de0... build: make use

Revert changes relative to lib/*.[ch] recent renaming

This reverts renaming and usage of lib/*.h header files done
28-12-2012, reverting 2 commits:

f871de0... build: make use of 76 lib/*.h renamed files
ffd8e12... build: rename 76 lib/*.h files

This also reverts removal of redundant include guard (redundant thanks
to changes in above commits) done 2-12-2013, reverting 1 commit:

c087374... curl_setup.h: remove redundant include guard

This also reverts renaming and usage of lib/*.c source files done
3-12-2013, reverting 3 commits:

13606bb... build: make use of 93 lib/*.c renamed files
5b6e792... build: rename 93 lib/*.c files
7d83dff... build: commit 13606bbfde follow-up 1

Start of related discussion thread:

http://curl.haxx.se/mail/lib-2013-01/0012.html

Asking for confirmation on pushing this revertion commit:

http://curl.haxx.se/mail/lib-2013-01/0048.html

Confirmation summary:

http://curl.haxx.se/mail/lib-2013-01/0079.html

NOTICE: The list of 2 files that have been modified by other
intermixed commits, while renamed, and also by at least one
of the 6 commits this one reverts follows below. These 2 files
will exhibit a hole in history unless git's '--follow' option
is used when viewing logs.

lib/curl_imap.h
lib/curl_smtp.h

show more ...

build: make use of 76 lib/*.h renamed files

76 private header files renamed to use our standard naming scheme.

This change affects 322 files in libcurl's source tree.

lib/*.h: use our standard naming scheme for header inclusion guards

source cleanup: unify look, style and indent levels

By the use of a the new lib/checksrc.pl script that checks that our
basic source style rules are followed.

IMAP in multi mode: use Curl_ssl_connect_nonblocking() when upgrading the connection to TLS/SSL.

IMAP in multi mode: use Curl_ssl_connect_nonblocking() when connecting.

remove the CVSish $Id$ lines

introducing IMAP, POP3 and SMTP support (still lots of polish left to do)