Merge branch 'session-hash' into dtls

* session-hash:
  Update Changelog for session-hash
  Make session-hash depend on TLS versions
  Forbid extended master secret with SSLv3
  compat.sh: allow git version of gnutls
  compat.sh: make options a bit more robust
  Implement extended master secret
  Add negotiation of Extended Master Secret

Conflicts:
	include/polarssl/check_config.h
	programs/ssl/ssl_server2.c