Tiddlyweb

* Code cleanups required for mounting TiddlyWeb at /
under mod_python.
* Argument handling fixes in twanager.

* Fairly critical performance fix when loading large TiddlyWikis.
* Change the twanager server command and tiddlyweb.config so
it is possible to run just 'twanager server' and get some
reasonable defaults.

* When creating an instance, establish a unique MAC secret.
* Rejigger how Etags are created for collections of tiddlers
to address a caching related bug when renaming.
* Lots of code reformatting based on pep8.py and pylint.
* Potentially memory management bug fixes.
* Cache bag permissions when performing a search in the
text store.

* Various changes to enable client side rename of tiddlers:
** Add server.title attribute to wiki serialization of
tiddlers to support client side renaming.
** Add Etag handling when POST to revisions collection.
** Add optional Etag handling when DELETE a tiddler.
* Use html5lib to parse tiddly content (into a
BeautifulSoup tree).

* Make sure that we enforce the use of an older BeautifulSoup
to avoid errors while parsing TiddlyWiki files
* urllib.quote escapes () but javascript encodeURIComponent does
not, leading to Etag comparison errors. Fixed.
* If the tiddlyweb.usersign is GUEST accept modifier value
in PUT Tiddlers.
* Add some code that shows how to use mod_wsgi to mount TiddlyWeb.

* support for user_delete from text store
* reading the policy of a bag now requires the manage permission
(instead of read)
* set DefaultTiddlers when sending one tiddler as a wiki
* correctly escape '/' in server side generation of etags