Add x86_64 to tested platforms.

Recvmsg is not fixed yet in Go release Dec 27 .

* Introduce RawFileSystem as direct interface to FUSE kernel layer,
  similar to fuse_lowlevel.h

* Introduce PathFuseFilesystem as path based interface, similar to
  fuse.h.

* Add connector to hook up PathFuseFilesystem with RawFileSystem
  interface.

* Add PassThroughFuse, which exposes os and syscall APIs as a FUSE
  PathFuseFilesystem, for testing.

* Add passthrough_test.go which exercises all of the API.

* Add fuse/README with explicit license notice and some information.

* Remove old 'manager' based API.

Port FUSE bindings to Go release.2010-12-15.1. Review URL: http://codereview.appspot.com/3807042/ Author: Han-Wen Nienhuys <hanwen@google.com>. Committer: Ivan Krasin <imkrasin@gmail.com>

This reverts commit a25a48d9.

Get rid of returning os.Error within dispatch switch. Now I had to add several panics. TODO: remve them in the future

Added some statuses to fuse.Status. Get rid of managerResponse.err. All errors are reported via managerResponse.code