merged upnp fix from RC_0_16

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@10004 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
only attempt to set the TOS on socket when configured

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@10005 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
fix support for web servers not supporting keepalive

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@10006 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
update changelog

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@10008 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda