Update devicetree sources and bindings, switch to new GPIO API. Use devicetree property name to identify interrupt signal. Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
Use nrf52_pca20020 and nrf51_ble400 to demonstrate the new functionality of the CCS811 driver. Signed-off-by: Peter A. Bigot <pab@pabigot.com>