export fswatcher to a separate library

vendor/gitlab.com/etke.cc/go/fswatcher/README.md

@@ -0,0 +1,11 @@
+# fswatcher
+
+A handy wrapper around [fsnotify](https://github.com/fsnotify/fsnotify) with deduplication
+
+```go
+watcher := fswatcher.New([]string{"/tmp/your-file.txt"}, 0)
+defer watcher.Stop()
+go watcher.Start(func(e fsnotify.Event){
+	// do something with event
+})
+```