Add ExtendedSSLSession, et al.

In order to support SNI certificate selection of the server-side and
enhanced certificate verification on the client side, we add
ExtendedSSLSession and the getHandshakeSession support.

This is just to set up for future implementations of SNI and
ExtendedX509TrustManager and doesn't actually implement the logic needed
to fully support the new features.

Change-Id: I300d3134d8ab9c184d6473183612dc53658a8221
5 files changed