actual DSi camera support (#1520)

basically feeding something that isn't a fixed stripe pattern, and emulating enough of the camera hardware to make this work

src/NDS.h

@@ -260,6 +260,7 @@ void SetKeyMask(u32 mask);
 bool IsLidClosed();
 void SetLidClosed(bool closed);
 
+void CamInputFrame(int cam, u32* data, int width, int height, bool rgb);
 void MicInputFrame(s16* data, int samples);
 
 void ScheduleEvent(u32 id, bool periodic, s32 delay, void (*func)(u32), u32 param);