Start replacing SD with SdFat, but it's not finished yet

.gitmodules

@@ -13,3 +13,6 @@
 [submodule "iot/libraries/Arduino-MemoryFree"]
 	path = iot/libraries/Arduino-MemoryFree
 	url = https://github.com/mpflaga/Arduino-MemoryFree.git
+[submodule "iot/libraries/SdFat"]
+	path = iot/libraries/SdFat
+	url = https://github.com/greiman/SdFat.git

iot/libraries/SdFat

@@ -0,0 +1 @@
+Subproject commit 3b79f38cb554809a45a0ccd6d9d6752b6ad948c2

iot/main/storage.cpp

@@ -1,19 +1,14 @@
 #include <Arduino.h>
-#include <SD.h>
-#include <TinyGPS++.h>
+#include <SdFat.h>
 
 #include "settings.h"
 #include "gps.h"
 
-void store_init() {
-	// NOTE: If this doesn't work, then we need to use pinMode() & specify the data pin here instead.
-	if(!SD.begin(PIN_SPI_CS_SD)) {
-		Serial.println(F("Error: MicroSD card init failed"));
-		while(true) { delay(1); } // Pseudo-halt, but uses delay() to ensure we keep passing back control to allow easy re-programming
-	}
-}
+SdFat* card = NULL;
 
 void store_reading(uint32_t id, GPSLocation location) {
+	SdFat card;
+	card.begin()
 	// Open the file to  write the data to. If it doesn't exist it will be created.
 	// Unlike elsewhere, FILE_WRITE opens the file with the cursor starting at the end, so it's basically actually equivalent to FILE_APPEND that we use in other environments. Confusing, I know.
 	File handle = SD.open(SD_FILENAME, FILE_WRITE);
@@ -36,7 +31,3 @@ void store_debug(char* buffer, int size) {
 	handle.println();
 	handle.close();
 }
-
-void store_close() {
-	SD.end();
-}