a lot of changes (0.03 API):

- added unlink (rm) method to invalidate in-memory cache
- added fuse_module_loaded method to check if fuse module is loaded
- fixed short read of last block
- removed Proc::Simple usage and replaced with simplier forking mechanism

This is first working version, but it's not binary-safe yet. NULL bytes
are still problem.

git-svn-id: svn://svn.rot13.org/fuse_dbi/trunk@21 17f4e80c-d0e0-0310-8903-bfc3ae804c12