add filesystem support(without frontend)

lib/units/websocket/index.js

@@ -826,6 +826,16 @@ module.exports = function(options) {
             )
           ])
         })
+        .on('fs.retrive', function(channel, responseChannel, data) {
+          joinChannel(responseChannel)
+          push.send([
+            channel
+          , wireutil.transaction(
+              responseChannel
+            , new wire.FileSystemGetMessage(data)
+            )
+          ])
+        })
     })
     .finally(function() {
       // Clean up all listeners and subscriptions