Add secure heap for storage of private keys (when possible).
Add BIO_s_secmem(), CBIGNUM, etc.
Add BIO_CTX_secure_new so all BIGNUM's in the context are secure.
Contributed by Akamai Technologies under the Corporate CLA.
Reviewed-by: Richard Levitte <levitte@openssl.org>
which is redundant. They are now in their own document.
Also, in the name section, all the functions described shoud be
enumerated. This will also make it much simpler to generate softlinks
name like each function to man-pages containing the info.