Added Plugin support (#102)

* Build refactoring and initial plugin support

* Possibly fixed linux / mac build

* Added libdl to libglad build script

* Add glfw to imgui dependencies

* Refactored common functionality into "libimhex" for plugins

* Added plugin loading and example plugin

* Added proper API for creating a custom view and a custom tools entry with plugins

plugins/libimhex/include/views/view.hpp

@@ -0,0 +1,71 @@
+#pragma once
+
+#include <hex.hpp>
+
+#include "imgui.h"
+
+#include "helpers/event.hpp"
+
+#include <functional>
+#include <string>
+#include <vector>
+
+
+namespace hex {
+
+    class View {
+    public:
+        View(std::string viewName);
+        virtual ~View() = default;
+
+        virtual void drawContent() = 0;
+        virtual void drawMenu();
+        virtual bool handleShortcut(int key, int mods);
+
+        static std::vector<std::function<void()>>& getDeferedCalls();
+
+        static void postEvent(Events eventType, const void *userData = nullptr);
+
+        static void drawCommonInterfaces();
+
+        static void showErrorPopup(std::string_view errorMessage);
+
+        static void setWindowPosition(s32 x, s32 y);
+
+        static const ImVec2& getWindowPosition();
+
+        static void setWindowSize(s32 width, s32 height);
+
+        static const ImVec2& getWindowSize();
+
+        virtual bool hasViewMenuItemEntry();
+        virtual ImVec2 getMinSize();
+        virtual ImVec2 getMaxSize();
+
+        bool& getWindowOpenState();
+
+        const std::string getName() const;
+
+    protected:
+        void subscribeEvent(Events eventType, std::function<void(const void*)> callback);
+
+        void unsubscribeEvent(Events eventType);
+
+        void doLater(std::function<void()> &&function);
+
+    protected:
+        void confirmButtons(const char *textLeft, const char *textRight, std::function<void()> leftButtonFn, std::function<void()> rightButtonFn);
+    private:
+        std::string m_viewName;
+        bool m_windowOpen = false;
+
+        static inline EventManager s_eventManager;
+        static inline std::vector<std::function<void()>> s_deferedCalls;
+
+        static inline std::string s_errorMessage;
+
+        static inline ImVec2 s_windowPos;
+        static inline ImVec2 s_windowSize;
+    };
+
+}