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

Added FileSystem.Lookup(parent, filename). It works. Also, I see that if I do several ls, the program stucks

The problem was in the test. I didn't allocate the memory for output parameter. But runtime was wrong with the line of code

Crash reproduced on a smaller range. I don't call any system call here, so the problem supposed to be located