Improve Keypad reading (let the pullup some time to charge the keys before sampling)

--And improve documentation to not be dependant from external sources.

FingerprintDoorbell/lib/Keypad/src/Keypad.cpp

@@ -85,7 +85,7 @@ void Keypad::scanKeys() {
 	for (byte r=0; r<sizeKpd.rows; r++) {
 		pin_mode(rowPins[r],INPUT_PULLUP);
 	}
-
+	delayMicroseconds(1);	// Let pins settle.
 	// bitMap stores ALL the keys that are being pressed.
 	for (byte c=0; c<sizeKpd.columns; c++) {
 		pin_mode(columnPins[c],OUTPUT);