Fix XMPP code detection on s_client starttls xmpp

 * Some XMPP Servers (OpenFire) use double quotes.
 * This makes s_client starttls work with this servers.
 * Tested with OpenFire servers from http://xmpp.net/ ::

     openssl s_client -connect coderollers.com:5222 -starttls xmpp
Fix infinite loop on s_client starttls xmpp

 * When the host used in "-connect" is not what the remote XMPP server expects
   the server will return an error like this:
     <stream:error>
       <host-unknown xmlns='urn:ietf:params:xml:ns:xmpp-streams'/>
     </stream:error>
 * But the actual code will stay on the loop forever because the stop condition
   "/stream:features>" will never happen,
 * Make this more robust: The stop condition should be that BIO_read failed
 * Test if for example with ::

    openssl s_client  -connect random.jabb3r.net:5222 -starttls xmpp
Add "xmpp" to the list of supported starttls protocols on s_client manpage
Add an "-xmpphost" option to s_client

 * Many XMPP servers are configured with multiple domains (virtual hosts)
 * In order to establish successfully the TLS connection you have to specify
   which virtual host you are trying to connect.
 * Test this, for example with ::
   * Fail:
       openssl s_client -connect talk.google.com:5222 -starttls xmpp
   * Works:
       openssl s_client -connect talk.google.com:5222 -starttls xmpp -xmpphost gmail.com
Clean up layout.
misspellings fixes by https://github.com/vlajos/misspell_fixer
s/recommend/recommended/
Add callbacks supporting generation and retrieval of supplemental data entries, facilitating RFC 5878 (TLS auth extensions)
Removed prior audit proof logic - audit proof support was implemented using the generic TLS extension API
Tests exercising the new supplemental data registration and callback api can be found in ssltest.c.
Implemented changes to s_server and s_client to exercise supplemental data callbacks via the -auth argument, as well as additional flags to exercise supplemental data being sent only during renegotiation.
Make it build.
More cleanup.
Free generated supp data after handshake completion, add comment regarding use of num_renegotiations in TLS and supp data generation callbacks
Const fix.
Set TLS v1.2 disabled mask properly.
Experimental encrypt-then-mac support.

Experimental support for encrypt then mac from
draft-gutmann-tls-encrypt-then-mac-02.txt

To enable it set the appropriate extension number (0x10 for the test server)
using e.g. -DTLSEXT_TYPE_encrypt_then_mac=0x10

For non-compliant peers (i.e. just about everything) this should have no
effect.
Document extension clash.
Partial path fix.

When verifying a partial path always check to see if the EE certificate
is explicitly trusted: the path could contain other untrusted certificates.
Remove ancient PATENTS section and FAQ reference.