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

plugins/libimhex/include/hex/api/content_registry.hpp

@@ -17,6 +17,7 @@ namespace hex {
     class View;
     namespace lang { class ASTNode; }
     namespace lang { class Evaluator; }
+    namespace dp { class Node; }
 
     /*
         The Content Registry is the heart of all features in ImHex that are in some way extendable by Plugins.
@@ -144,6 +145,26 @@ namespace hex {
 
             static std::vector<Entry>& getEntries();
         };
+
+        struct DataProcessorNode {
+            using CreatorFunction = std::function<dp::Node*()>;
+            struct Entry {
+                std::string category;
+                std::string name;
+                CreatorFunction creatorFunction;
+            };
+
+            template<hex::derived_from<dp::Node> T, typename ... Args>
+            static void add(std::string_view category, std::string_view name, Args&& ... args) {
+                add(Entry{ category.data(), name.data(), [args...]{ return new T(std::forward<Args>(args)...); } });
+            }
+
+            static void addSeparator();
+
+            static std::vector<Entry>& getEntries();
+        private:
+            static void add(const Entry &entry);
+        };
     };
 
 }