Forgot a few instances of dupes_file.
* Rewrote dupe_trees completely. Seems to be a problem with the fingerprints. Need to look into more deeply.
* Added back in parser option for diff trees.
* Started on another rewrite of dupe_trees.
* Latest pass of dupe_trees algorithm properly detects dupes. Now need to only report "subroots".
* dupe_trees appears to be working except that it doesn't properly detect matching roots.
* Fixed a bug in gen_db_url caused by passing in a root as item.
* dupe_trees works now.