ll: Implementation of passive scanning

Conflicts:
	stack/ll.c
	stack/ll.h
examples: Add LL Scanner example
examples: Add LL Scanner example

Conflicts:
	examples/ll-scanner/main.c
nrf51822/log: disable UART flow control
ll: Draft for connection initiating state (no Connection state yet)
stack: Add Random number generation API
nrf51822/random: implement random API using RNG peripheral
ll: Fix interval timer callback in initiating state
ll: implemented data channel map & index selection for connection states