Switch SD2cadrLib to fastio

Replace all fastDigitalRead/Write() with READ/WRITE()

Define SCK_PIN, MISO_PIN, MOSI_PIN in pins.h if not already defined in the pins_*.h files.

Remove these conditional pin definitions from the pin-files. They are now always defined.

Define separate sets of SPI-pins for AT90USB with and without Teensy support in fastio.h.
Likely this was the main reason for all that confusion about the AT90USB-SPI pins.

Marlin/MarlinConfig.h

@@ -23,6 +23,7 @@
 #ifndef MARLIN_CONFIG_H
 #define MARLIN_CONFIG_H
 
+#include "fastio.h"
 #include "macros.h"
 #include "boards.h"
 #include "Version.h"