Cache - Serializing page contents as readable text files

Currently, when a page is cached, it is serialized on the filesystem using the default Java serialization mechanism. This raises two issues:

1) pages cannot be deserialized if the Java source code has changed
2) page contents cannot be read easily from an external file editor, or used for latex processing etc.

I propose that document gets stored in their own folder (with a folder for each space as well). The folder name would be the document's name. The folder would contain several files: the document's content, its attachments, its metadata in XML and its attached objects in XML.