nrf24-config: setMode(): pulse CE after entering Tx and set CE afterwards, also               clear IRQ flags and flush Rx Fifo when entering Rx mode
nrf24-config: setMode(): pulse CE after entering Tx and set CE afterwards, also
              clear IRQ flags and flush Rx Fifo when entering Rx mode

dergraaf/xpcc,chrism333/xpcc,chrism333/xpcc,chrism333/xpcc,chrism333/xpcc,dergraaf/xpcc,dergraaf/xpcc,dergraaf/xpcc