* Improve backward compatibility of the new SSL implementation.
* Add wrapper for SSL_CTX_set_default_verify_paths().
* Document which OpenSSL functions the ssl::context member functions use.
* Add SSL certificate verification callbacks, and add a new
ssl::rfc2818_verification function object for simple peer certificate
verification based on the host name.
* Use std::atomic<> when available.
* Prefer to use std::array when it is available.
* Use std::shared_ptr and std::weak_ptr when available.
* Use a lightweight scoped smart pointer.
* Fix some shadow variable warnings with g++ 4.6.
[SVN r70384]
