A plugin for TiddlyWeb subclassing tiddlywebplugins.sqlalchemy3 with mysql specifics.

The main additions to sqlalchemy3 are:

* Provide a reasonable search interface using mysql's fulltext.
* Provide field based searches of tiddler attributes and fields.
* Support finding tiddlers that have geo.lat and geo.long fields
  near a location.
* Provide an index_query method to allow the plugin to be used as
  an 'indexer' for filters and determine_bag_for_tiddler.

NOTES

It's import to set some mysql my.cnf variables otherwise searches
will likely fail.

[mysqld]
ft_min_word_len = 3
ft_stopword_file = ''

You will need to create a database. I use one called 'tiddlyweb', and
add the following to tiddlywebconfig.py:

    'server_store': ['tiddlywebplugins.mysql', {
        'db_config': 'mysql:///tiddlyweb?charset=utf8&use_unicode=0'}],
    'indexer': 'tiddlywebplugins.mysql',

If you want to use the fulltext indexing capability you will need to
create the fulltext index:

    CREATE FULLTEXT INDEX tiddlytext ON text(text);

Thanks to Adrian Hosey <http://adrianhosey.blogspot.com/> for help over
some SQL humps.
