refactor example + adding imgui and imtui submodules

examples/ggwave-common-sdl2.h

@@ -2,13 +2,17 @@
 
 #include <SDL.h>
 
+#include <string>
+
 class GGWave;
 
-bool initSDL2ForGGWave(
-        bool & isInitialized,
-        const int playbackId,
-        SDL_AudioDeviceID & devIdIn,
-        const int captureId,
-        SDL_AudioDeviceID & devIdOut,
-        GGWave *& ggWave,
-        const char * defaultCaptureDeviceName = nullptr);
+// GGWave helpers
+
+void GGWave_setDefaultCaptureDeviceName(std::string name);
+bool GGWave_init(const int playbackId, const int captureId);
+GGWave * GGWave_instance();
+bool GGWave_mainLoop();
+bool GGWave_deinit();
+
+// ImGui helpers
+