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.

src/AutoLilvNode.hpp

@@ -63,6 +63,14 @@ namespace pipedal
         {
             Free();
             this->node = node;
+            this->isConst = false;
+            return *this;
+        }
+        AutoLilvNode &operator=(const LilvNode *node)
+        {
+            Free();
+            this->node = const_cast<LilvNode*>(node);
+            this->isConst = true;
             return *this;
         }