Rename/migrate to Bundlecache and provide a stable D6 release.

As per #960162: Module ownership of sf_cache and bundlecache, I'm now the maintainer of the Support File Cache and Bundlecache modules. I discussed this with Konstantin Käfer and we agreed that it'd be better (at least for now) if I'd become the maintainer.

Why? My master thesis is all about WPO, and with that in mind, I'm trying to ramp up my WPO contributions to Drupal:
- version 2.0 of the CDN module is practically ready (http://drupal.org/project/cdn). I'll work on the D7 port for that module soon.
- the Episodes module (http://drupal.org/project/episodes) will soon also be updated, as Steve Souders finally released Episodes 2 today (http://stevesouders.com/episodes2/)
- I'm trying to consolidate the myriad of Drupal WPO modules. E.g. users of the parallel module will be migrated to the cdn module: http://drupal.org/node/933942.

Apparently Konstantin ported sf_cache to Drupal 7 (Drupal 7 HEAD as of June/July 2010) and renamed the module to bundlecache, which is a name that's both more legible and more sensible. He committed this module right away so I could continue from there. We agreed that it'd be best to rename the D6 version of sf_cache to bundlecache and provide an upgrade path. From there, I'll continue development.

I'm sure I've forgotten to mention something here, but I can add that later :)

Hopefully, I'll be able to make good progress with this module and gain more users :)