Added Data Processor using Nodes (#152)

* Added imnodes

* Added basic data processor view. Still needs to be cleaned up

* Make sure all attached links get properly removed when a Node is deleted

* Cleanup and API exposing

* Added data provider overlays and integrate them with the data processor

* Optimized data processing

* Node UI enhancements

* Added support for all themes to the nodes editor

* Improved data processor context menus

* Fixed data processor context menu showing up everywhere

* Make hex editor context menu behave the same as data processor one

* Add different node pin types and prevent incompatible ones from being connected

* Don't require explicitly marking node as end node

* Fixed plugin copying

* Added some more nodes

include/views/view_data_processor.hpp

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <hex.hpp>
+
+#include <imgui.h>
+#include <hex/views/view.hpp>
+#include <hex/data_processor/node.hpp>
+#include <hex/data_processor/link.hpp>
+
+#include <array>
+#include <string>
+
+namespace hex {
+
+    namespace prv { class Provider; }
+
+    class ViewDataProcessor : public View {
+    public:
+        ViewDataProcessor();
+        ~ViewDataProcessor() override;
+
+        void drawContent() override;
+        void drawMenu() override;
+
+    private:
+        std::list<dp::Node*> m_endNodes;
+        std::list<dp::Node*> m_nodes;
+        std::list<dp::Link>  m_links;
+
+        std::vector<prv::Overlay*> m_dataOverlays;
+
+        int m_rightClickedId = -1;
+        ImVec2 m_rightClickedCoords;
+
+        void eraseLink(u32 id);
+        void eraseNodes(const std::vector<int> &ids);
+        void processNodes();
+    };
+
+}