A TiddlyWeb plugin which adds a _hash field to outgoing tiddlers.

* When a tiddler is get from the store, if there is no _hash, then the
  hash is added to the outgoing tiddler. It is _not_ saved

This is done to allow quick comparisons between tiddlers which may have
different names but may have the same set of content characteristics.

By default the attribute from which the digest is created is 'text'.

A future version will also write the _hash on a put. This is not done
now because there's no mechanism that will consistently work for this.

Copyright 2010, Chris Dent <cdent@peermore.com>

Licensed under the same terms as TiddlyWeb.
