Basic LOCK/UNLOCK support for WebDAV
Add If header processing
Be more careful about release netty buffers
Implement simple Redis connection pool, because Redis is connection orientated
Implement MKDIR webdav command
Support delete, also fix some encoding issues and similar bugs

When we delete, we don't actually delete, we just remove it from the name tree.

To enable GC or undelete, we write a record of the deleted inodes in the 'X' keyspace
Support MOVE