Experiment with using redis as a store for TiddlyWeb.

You must be running a redis server for the tests to pass. The 'redis' module
for Python is required. If you have hiredis, parsing will be improved.

This code supports the full StorageInterface, including policies and
tiddler revisions.

It makes no assumptions about how you are managing your redis server.
You will need to start that, and if you use any non-default configuration
you will need to put that in tiddlywebconfig.py. For example if you want
do use db 5, then you could have:

    config = {
        'server_store': ['redisstore', {'db': 5}],
    }

!ToDo

* Consider m{get,set} for some of the {gets,sets}.

* Consider using r->keys('tid:1:*') and similar to gather keys for
  deletion. This may not be ideal though, as matching for keys when
  there are many may be expensive.

* Dealing with keys that might have ':' in them.

* Manage keys that operate as reverse indexes for things we might
  like to index_query, such as modifier, tags and fields. This has
  not been done thus far as diddling with that would distract from
  getting the core set of keys in place. Something like

    tags:<tagname>:tids => set of tids that have that tag

* Consider reverse indexes for things like bags in recipes, and 
  users in policies. (Such things have been useful in TiddlySpace).
  Again these are not yet done so as to maintain focus.

* See what the options are for pub/sub.

!Copyright Etc

Copyright 2011, Chris Dent <cdent@peermore.com>
Released under the BSD License