back-port test port fix

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@9014 a83610d8-ad2a-0410-a6ab-fc0612d85776
back port check to not destruct session_impl from its own thread

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@9015 a83610d8-ad2a-0410-a6ab-fc0612d85776
build python bindings as part of regression tests

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@9016 a83610d8-ad2a-0410-a6ab-fc0612d85776