Changed the naming of some LCD functions, so the names match better what the function does. Also moved around some prototypes for general cleanup.

Marlin/cardreader.h

@@ -69,6 +69,17 @@ private:
 extern CardReader card;
 #define IS_SD_PRINTING (card.sdprinting)
 
+#if (SDCARDDETECT > -1)
+# ifdef SDCARDDETECTINVERTED 
+#  define IS_SD_INSERTED (READ(SDCARDDETECT)!=0)
+# else
+#  define IS_SD_INSERTED (READ(SDCARDDETECT)==0)
+# endif //SDCARDTETECTINVERTED
+#else
+//If we don't have a card detect line, aways asume the card is inserted
+# define IS_SD_INSERTED true
+#endif
+
 #else
 
 #define IS_SD_PRINTING (false)