most unused arg warnings corrected.

- removed deprecated bitmap arg from IMB_allocImBuf (plugins will need updating).
- mostly tagged UNUSED() since some of these functions look like they may need to have the arguments used later.

source/gameengine/GamePlayer/ghost/GPG_Application.cpp

@@ -583,7 +583,7 @@ bool GPG_Application::initEngine(GHOST_IWindow* window, const int stereoMode)
 		if (!m_networkdevice)
 			goto initFailed;
 			
-		sound_init(m_maggie);
+		sound_init();
 
 		// create a ketsjisystem (only needed for timing and stuff)
 		m_kxsystem = new GPG_System (m_system);