added module system

modules/demo/src/main.cpp

@@ -0,0 +1,26 @@
+#include <imgui.h>
+#include <module.h>
+
+mod::API_t* API;
+
+struct DemoContext_t {
+    std::string name;
+};
+
+MOD_EXPORT void* _INIT_(mod::API_t* _API, ImGuiContext* imctx, std::string _name) {
+    API = _API;
+    DemoContext_t* ctx = new DemoContext_t;
+    ctx->name = _name;
+    ImGui::SetCurrentContext(imctx);
+    return ctx;
+}
+
+MOD_EXPORT void _DRAW_MENU_(DemoContext_t* ctx) {
+    char buf[100];
+    sprintf(buf, "I'm %s", ctx->name.c_str());
+    ImGui::Button(buf);
+}
+
+MOD_EXPORT void _STOP_(DemoContext_t* ctx) {
+    delete ctx;
+}