improve node-id generation for DHT maintanence calls

git-svn-id: svn://svn.code.sf.net/p/libtorrent/code@10462 a83610d8-ad2a-0410-a6ab-fc0612d85776
improve DHT bootstrapping and periodic refresh

git-svn-id: svn://svn.code.sf.net/p/libtorrent/code@10463 a83610d8-ad2a-0410-a6ab-fc0612d85776
fix dht log parsing script

git-svn-id: svn://svn.code.sf.net/p/libtorrent/code@10464 a83610d8-ad2a-0410-a6ab-fc0612d85776