Initial commit of SSLSocket implementation as adapter of SSLEngine.
Needed on Android due to broken SSLSocket in harmony classpath.
Make more robust by not necessarily blowing up upon access to
unsupported socket option, by providing a dummy FileDescriptor, and by
only closing underlying stream one time.
SSLSocketFactory for creating SSLEngineSSLSocket instances
If Android runtime detected, use AndroidSSLSocketFactory to create
SSLSocket instances