add stdint.h to ssl.h.

ok jsing@
Add support for ALPN.

Based on OpenSSL and BoringSSL.

ok bcook@
libssl major++
Remove support for GOST R 34.10-94 signature authentication, along with
the two ciphersuites that use it. GOST94 public/private keys have been
long obsoleted and libcrypto does not have support for them anyway.

Discussed with Dmitry Eremin-Solenikov.
ssl3_init_finished_mac() calls BIO_new() which can fail since it in turn
calls malloc(). Instead of silently continuing on failure, check the return
value of BIO_new() and propagate failure back to the caller for appropriate
handling.

ok bcook@