Toob Flanger, Stereo Reverb, bug fixes

- support state in factory presets.
- Use uncompressed json for settings files.
- Set current plugin preset name to last loaded plugin preset.
- Append plugins after  start node,  before end node fixed.
- Correctly release web socket when web app goes idle.
- Fit and finish issues.

react/src/PiPedalSocket.tsx

@@ -214,7 +214,7 @@ class PiPedalSocket {
     enterBackgroundState()
     {
         this.isBackground = true;
-        this.socket?.close();
+        this.close();
 
     }
     exitBackgroundState()
@@ -261,7 +261,7 @@ class PiPedalSocket {
                 this.socket.onerror = null;
                 this.socket.onmessage = null;
                 this.socket.onopen = null;
-                this.socket?.close();
+                this.socket.close();
             }
         } catch  (ignored)
         {