Merge headers from nitro decomp (#69)

* merge headers from nitro decomp

* cleanup: use inlines from g2.h and gx.h when changing registers

* cleanup: remove externs declarations in source files

include/Game/GameModeManager.hpp

@@ -5,11 +5,11 @@
 #include "Player/TouchControl.hpp"
 #include "System/SysNew.hpp"
 #include "Unknown/UnkStruct_02049b18.hpp"
+#include "input.hpp"
 #include "math.hpp"
 #include "types.h"
 
-#include <nitro/button.h>
-#include <nitro/touch.h>
+#include <nitro/tp.h>
 
 class GameModeManagerBase;
 class GameModeManagerBase_104;