Support rust-openssl 0.9 #36

Hi,

I've been trying to update solicit to support rust-openssl 0.9, and I'm almost there. The last issue is to implement try_split for SslStream<TcpStream>, but the underlying method try_clone for SslStream was deprecated in rust-openssl 0.8.

Has anybody else tried to update this? One option is to go with Arc<Mutex<_>>, but I'd like to know is there any simpler solution here...

Ping @jwilm et.al.