Log Message:
Changes 1.3.3:
** New API to access the TLS master secret.
When possible, you should use the TLS PRF functions instead.

** Improved handling when multiple libraries use GnuTLS at the same time.
Now gnutls_global_init() can be called multiple times, and
gnutls_global_deinit() will only deallocate the structure when it has
been called as many times as gnutls_global_init() was called.

** Added a self test of TLS resume functionality.

** Fix crash in TLS resume code, caused by TLS/IA changes.

** Add 'const' keywords in various places, from Frediano ZIGLIO.

** The code was indented again, including the external header files.

** API and ABI modifications:
New functions to retrieve the master secret value:
  gnutls_session_get_master_secret

Add a 'const' keyword to existing API:
  gnutls_x509_crq_get_challenge_password