NDOF: compile 3D mouse code only if WITH_INPUT_NDOF

When WITH_INPUT_NDOF is disabled, 3D mouse handling code is removed
from:

- GHOST (was mostly done, finished the job)
- window manager
- various editors
- RNA
- keymaps

The input tab of user prefs does not show 3D mouse settings. Key map
editor does not show NDOF mappings.

DNA does not change.

On my Mac the compiled binary is 42KB smaller after this change. It
runs fine WITH_INPUT_NDOF on or off.

intern/ghost/intern/GHOST_System.cpp

@@ -38,11 +38,13 @@
 
 #include "GHOST_DisplayManager.h"
 #include "GHOST_EventManager.h"
-#include "GHOST_NDOFManager.h"
 #include "GHOST_TimerTask.h"
 #include "GHOST_TimerManager.h"
 #include "GHOST_WindowManager.h"
 
+#ifdef WITH_INPUT_NDOF
+#  include "GHOST_NDOFManager.h"
+#endif
 
 GHOST_System::GHOST_System()
     : m_nativePixel(false),
@@ -292,14 +294,12 @@ GHOST_TSuccess GHOST_System::getButtonState(GHOST_TButtonMask mask, bool& isDown
 	return success;
 }
 
+#ifdef WITH_INPUT_NDOF
 void GHOST_System::setNDOFDeadZone(float deadzone)
 {
-#ifdef WITH_INPUT_NDOF
 	this->m_ndofManager->setDeadZone(deadzone);
-#else
-	(void)deadzone;
-#endif
 }
+#endif
 
 GHOST_TSuccess GHOST_System::init()
 {
@@ -345,6 +345,7 @@ GHOST_TSuccess GHOST_System::exit()
 	delete m_ndofManager;
 	m_ndofManager = NULL;
 #endif
+
 	return GHOST_kSuccess;
 }