1.0.1

1. Raise exception if Oplog/Tailer/TailThread.py exits before starting oplog tailing
2. Fix for '[Errno 39] Directory not empty' when mongodump dump dir already exists (never happens, really)
3. Return correct existing-backup count in State:load_backups log-line
4. Use lockfile to prevent concurrent access to ZBackup storage dir (ZBackup isn't really concurrent)
5. README updates
6. Dockerfile update to add 'zbackup' dependency to image
7. Added script to run Docker container with persistent data volumes