The overhead of Zend_Cache in manifests is too high - we don't
need LRU or tags, just somewhere to dump a bunch of data that
persists
You can replace the class used by defining SS_MANIFESTCACHE
to be a class that implements the ManifestCache interface
(we can't use the Config system to set this, as it isn't
initialised yet).
Resolves an issue where if not using the themes directory (i.e just a single app folder) you cannot override module templates.
Changes the SS_TemplateManifest constructor with a new $project argument.
