Add project files.

vendor/imgui/include/imgui_sdl.h

@@ -0,0 +1,17 @@
+#pragma once
+
+struct ImDrawData;
+struct SDL_Renderer;
+
+namespace ImGuiSDL
+{
+	// Call this to initialize the SDL renderer device that is internally used by the renderer.
+	void Initialize(SDL_Renderer* renderer, int windowWidth, int windowHeight);
+	// Call this before destroying your SDL renderer or ImGui to ensure that proper cleanup is done. This doesn't do anything critically important though,
+	// so if you're fine with small memory leaks at the end of your application, you can even omit this.
+	void Deinitialize();
+
+	// Call this every frame after ImGui::Render with ImGui::GetDrawData(). This will use the SDL_Renderer provided to the interfrace with Initialize
+	// to draw the contents of the draw data to the screen.
+	void Render(ImDrawData* drawData);
+}