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/json.cpp

@@ -23,11 +23,12 @@
 #include <cctype>
 #include "PiPedalException.hpp"
 #include "json_variant.hpp"
-
+#include "util.hpp"
 using namespace pipedal;
 
 
 
+
 uint32_t json_writer::continuation_byte(std::string_view::iterator &p, std::string_view::const_iterator end)
 {
     if (p == end)