improve connection tester to support non-fast-extension clients and to be multi-threaded
improve connection tester to support non-fast-extension clients and to be multi-threaded

deluge-clone/libtorrent,deluge-clone/libtorrent,deluge-clone/libtorrent,deluge-clone/libtorrent,deluge-clone/libtorrent,deluge-clone/libtorrent