remove some constructors

Optional soft reset was added before, this can confuse ppl by default
set ss and not set rst pin. To clearify this change is made. Maybe
brakes some implmentations.

changes.txt

@@ -1,7 +1,11 @@
 -- Add changes to unreleased tag until we make a release.
 
 unreleased
--
+- Removed: void PCD_Init(byte resetPowerDownPin);
+- Removed: MFRC522(byte resetPowerDownPin);
+- Changed default initialisation of SS pin with constants of arduino.h are not done anymore
+- Replaced UINT8_MAX by UNUSED_PIN
+- 
 
 22 Mar 2017, v1.3.6
 - Added deprecate and compiler warnings @Rotzbua