branch for steven solito's patch to make peer connection encryption more generic

git-svn-id: svn://svn.code.sf.net/p/libtorrent/code@10512 a83610d8-ad2a-0410-a6ab-fc0612d85776
apply Steven Siloti's patch to generalize the encryption handler for peer_connections

git-svn-id: svn://svn.code.sf.net/p/libtorrent/code@10513 a83610d8-ad2a-0410-a6ab-fc0612d85776
add asserts to track down issue with new receive_buffer, and fix it. silence some construction-order warnings too

git-svn-id: svn://svn.code.sf.net/p/libtorrent/code@10514 a83610d8-ad2a-0410-a6ab-fc0612d85776