Merge branch 'master' of https://github.com/cbeighley/piksi_firmware
Call serial.Serial.close() method when SerialLink is closed
Don't call ser.close in SerialLink.close, instead wait for ListenerThread to close it then exit
Merge remote-tracking branch 'origin/master' into HEAD

Conflicts:
	scripts/serial_link.py
Add message for acquisition result
Put u8 at end of struct to avoid __packed__ alignment issues
Refactor acq result message
Take NAP authentication check out of init and put it after usarts_setup
so we can use printf in it rather than screaming_death.
Merge branch 'master' into hardware_bringup_improvements
NAP callbacks must be registered after sbp_setup
Add option to erase sectors 1-11 of STM flash when flashing new STM
firmware
Merge remote-tracking branch 'origin/master'
Add release notes.
Merge remote-tracking branch 'origin/master' into fix_device_dna

Conflicts:
	src/acq.c
	src/manage.c
	src/sbp_piksi.h
Merge commit '8a1c85b4aa2a6487786cffdc1315bde60c33ad5f' into fix_device_dna
Send acq results to host after each acquisition
Comment to explain NAP authentication check

NAP authentication check has to come after the NAP, USARTs, and SBP subsystem are set up - Piksi needs to be able to send and receive SBP messages while warning about an invalid FPGA key.
NMEA: Increase altitude accuracy to 1cm
PACKAGING: Fix issue with dmg packager, tmp dir was not being created
Remove commented out code, beautify comments.