overhauled client_test. refactored and simplified. still in progress

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@10088 a83610d8-ad2a-0410-a6ab-fc0612d85776
fixed chrono issue in dht

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@10089 a83610d8-ad2a-0410-a6ab-fc0612d85776
more work towards making client_test event-driven and use session stats counters instead of session_status + some refactoring

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@10090 a83610d8-ad2a-0410-a6ab-fc0612d85776