Update test server details.

     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

     To enable it set the appropriate extension number (0x42 for the test

     server) using e.g. -DTLSEXT_TYPE_encrypt_then_mac=0x42

     For non-compliant peers (i.e. just about everything) this should have no

     effect.

     WARNING: EXPERIMENTAL, SUBJECT TO CHANGE.

     NOTE: unfortunately the test server value (0x10) clashes with the draft

     ALPN extension. Until this is resolved the only way to check against the

     test server is to temporarily change the ALPN extension value (ugh!).

     [Steve Henson]

  *) Add callbacks supporting generation and retrieval of supplemental