Improved SRAM performance (#925)

* Offload NDS SRAM writing to separate thread, debounce writes to two seconds after last flush or DeInit.

* Fixed printf messages.

* Fixes after CR.

* Fixed potential portability issue with time_t

src/Platform.h

@@ -102,6 +102,8 @@ void LAN_DeInit();
 int LAN_SendPacket(u8* data, int len);
 int LAN_RecvPacket(u8* data);
 
+void Sleep(u64 usecs);
+
 }
 
 #endif // PLATFORM_H