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/CMakeLists.txt

@@ -33,6 +33,7 @@ add_library(core STATIC
 	melonDLDI.h
 	NDS.cpp
 	NDSCart.cpp
+	NDSCart_SRAMManager.cpp
 	Platform.h
 	ROMList.h
 	RTC.cpp