misc: add fuse2fs, a FUSE server for e2fsprogs

misc: add fuse2fs, a FUSE server for e2fsprogs

This is the initial implementation of a FUSE server based on
e2fsprogs.  The point of this program is to enable ext4 to run on any
OS that FUSE supports (and doesn't already have a native driver), such
as MacOS X, BSDs, and Windows.  The code requires FUSE API v28, which
is available in Linux fuse and osxfuse releases that are available as
of August 2013.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>