namenode: read dataNodeLocations from config file
mw3: lease is renewed when calling lock multiple times
mw3: added cd fir MWDFSClient
mw3: MWDFSClient supports ls
mw3: added remove to MWDFSClient
mw3: dirs can now be locked as well
mw3: added upload file to MWDFSClient
mw3: added download file to MWDFSClient