Squashed commit of the following:
drivers/bluetooth: Re-architect Bluetooth UART driver to follow upper/lower half model. Completely untested.
drivers/bluetooth: Grr.. Another band-aid commit to stay in sync with master. Why is this so difficult
drivers/bluetooth: Band-aid commit to stay in sync with master. Lost it somehow.
drivers/wireless/bluetooth: A few changes, mostly thought experiments.
drivers/wireless/bluetooth: UART-based Bluetooth driver ported from the Intel/Zephyr arduino101_firmware_source-v1.tar package. This initial commit is the original files in the NuttX build environment with changes to conform with the coding standard. It should not even build.