optimize piece printing in client_test

git-svn-id: svn://svn.code.sf.net/p/libtorrent/code@10371 a83610d8-ad2a-0410-a6ab-fc0612d85776
some DHT logging and parsing

git-svn-id: svn://svn.code.sf.net/p/libtorrent/code@10372 a83610d8-ad2a-0410-a6ab-fc0612d85776