KL46Z: Added Sleep, LED3 and LED4 definitions, switches

Sleep = KL25Z sleep (verified to work correctly)

LED3 = LED1, LED4 = LED2 (for compatibility, similar to LED3 = LED4 in
KL25Z code)

SW1 and SW3 for the two switches (SW2 is reset switch, pull-up needed in code to use them)

Extra one, also: https://mbed.org/questions/2309/spifrequency-for-KL25Z/ fixed