Fix import
Rename BaseLibrary -> Library in comments

Because removed BaseLibrary class
Add mktag and rmtag
Fix bug: path with trailing slashes

Path with trailing slashes to converted directory can't be tagged due to
quirks.  Path normalized to fix.
Fix bug: incorrect assertion
Fix corrupt JSON config loading bug
Restore BorderNode class
Fix JSON dumping
Fix recursive tree node dumping
Fix json.dump() call argument order