example: add doc comments to main programs

Change-Id: Iefe9bf5c77a332002b3b0a15b75853102549b511

example/hello/main.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// A Go mirror of libfuse's hello.c
-
+// This program is the analogon of libfuse's hello.c, a a program that
+// exposes a single file "file.txt" in the root directory.
 package main
 
 import (

example/loopback/main.go

@@ -2,9 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Mounts another directory as loopback for testing and benchmarking
-// purposes.
-
+// This is main program driver for the loopback filesystem from
+// github.com/hanwen/go-fuse/fs/, a filesystem that shunts operations
+// to an underlying file system.
 package main
 
 import (

example/multizip/main.go

@@ -2,6 +2,10 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// This is main program driver for MultiZipFs from
+// github.com/hanwen/go-fuse/zipfs, a filesystem for mounting multiple
+// read-only archives. It can be used by symlinking to an archive file
+// from the config/ subdirectory.
 package main
 
 import (

example/statfs/main.go

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// statfs is a main driver for the file system from
+// github.com/hanwen/go-fuse/benchmark, intended for benchmarking FUSE
+// libraries.
 package main
 
 import (

example/zipfs/main.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// This is main program driver for github.com/hanwen/go-fuse/zipfs, a
+// filesystem for mounting read-only archives.
 package main
 
 import (