sasl: Centralised the authentication mechanism strings

Moved the standard SASL mechanism strings into curl_sasl.h rather than
hard coding the same values over and over again in the protocols that
use SASL authentication.

For more information about the mechanism strings see:

http://www.iana.org/assignments/sasl-mechanisms
ftp.c: Fixed compilation warning

There is an implicit conversion from "unsigned long" to "long"
imap: Added clarification to the code about odd continuation responses
configure: use icc options without space

The latest version(s) of the icc compiler no longer accept the extra
space in the -we (warning enable), -wd (warning disable), etc.

Reported-by: Elmira A Semenova
Bug: http://curl.haxx.se/mail/lib-2013-09/0182.html
ssluse.c: Fixed compilation warnings when ENGINE not supported

The function "ssl_ui_reader" was declared but never referenced
The function "ssl_ui_writer" was declared but never referenced
win32: fix Visual Studio 2010 build with WINVER >= 0x600

If no WINVER and/or _WIN32_IWNNT define was set, the Windows platform
SDK often defaults to high value, e.g. 0x601 (whoch may probably depend
on the Windows version being used, in my case Windows 7).

If WINVER >= 0x600 then winsock2.h includes some defines for WSAPoll(),
e.g. POLLIN, POLLPRI, POLLOUT etc. These defines clash with cURL's
lib/select.h.

Make sure HAVE_STRUCT_POLLFD is defined then.

Bug: http://curl.haxx.se/bug/view.cgi?id=1282
Reported-by: "kdekker"
Patch-by: Marcel Raad
postinmemory: new example

This is similar to getinmemory.c but with an initial POST.

Combined-by: Ulf Samuelsson
getinmemory: remove a comment

The comment mentioned the need to free the data, but the example already
does that free
ftpserver.pl: Added unwanted argument check to SMTP DATA command handler
ftpserver.pl: Moved specifying the test number from the RCPT address

...to the client address as this frees the RCPT strings to contain
just an email address and by passing the test number into curl as the
client address remains consistent with POP3 and IMAP tests as they are
specified in the URL.
ftpserver.pl: Fixed compilation error from commit 49341628b50007
test909: Removed custom EHLO response after recent changes

...as it is no longer required following capability and authentication
changes and is now causing problems following commit 49341628b50007 as
the test number is obtained from the client address in the EHLO.
tests: Updated email addresses in SMTP tests following recent changes
tests: Fixed typos from commit 25a0c96a494297
curl_easy_setopt.3: slight clarification of SEEKFUNCTION
xattr: add support for FreeBSD xattr API
KNOWN_BUGS: #84: CURLINFO_SSL_VERIFYRESULT

CURLINFO_SSL_VERIFYRESULT is only implemented for the OpenSSL and NSS
backends and not for any other!
OpenSSL: acknowledge CURLOPT_SSL_VERIFYHOST without VERIFYPEER

Setting only CURLOPT_SSL_VERIFYHOST without CURLOPT_SSL_VERIFYPEER set
should still verify that the host name fields in the server certificate
is fine or return failure.

Bug: http://curl.haxx.se/mail/lib-2013-10/0002.html
Reported-by: Ishan SinghLevett
darwinssl: block TLS_RSA_WITH_NULL_SHA256 cipher

Credit (for catching a cipher I forgot to add to the blocked ciphers list):
https://www.ssllabs.com/ssltest/viewMyClient.html
RELEASE-NOTES: synced with 173160c0d068