Custom path support (#1333)

also including:
* getting rid of shitty strings
* all new, cleaner ROM handling code
* base for DSi savestates
* GBA slot addons (for now, memory cart)

src/AREngine.cpp

@@ -50,8 +50,6 @@ void DeInit()
 
 void Reset()
 {
-    CodeFile = nullptr;
-
     if (NDS::ConsoleType == 1)
     {
         BusRead8 = DSi::ARM7Read8;
@@ -73,6 +71,11 @@ void Reset()
 }
 
 
+ARCodeFile* GetCodeFile()
+{
+    return CodeFile;
+}
+
 void SetCodeFile(ARCodeFile* file)
 {
     CodeFile = file;