moved event_queue to state singleton

src/clipboard.cpp

@@ -0,0 +1,16 @@
+#include "clipboard.h"
+
+namespace VISEQ::APP {
+    GRAPH::NODES::VEC_SPTR_Node Clipboard::pasteNodes(){
+        return clipboard.back();
+    }
+
+    void Clipboard::copyNodes(GRAPH::NODES::VEC_SPTR_Node selected_nodes){
+        if(clipboard.size() == 20) clipboard.pop_back();
+        clipboard.emplace(clipboard.begin());
+        for(auto n : selected_nodes){
+            clipboard.front().push_back(n);
+        }
+    }
+
+}