Refactor packet class; add PacketType enum.
Add enum to requirements.txt
Fix packet_type, replace packet constants in frame consumer
Fix variable names for adc-3 to adc_3
Use new packet object in sensor_reading
Update packet comments
Merge master into improve-packet
Stub out packet test cases
Get nd packet passing
Fix nt packet support
Add green passing tests
Move all the packet reflection to classes (where it belongs)
Remove unneccesary class get_packet_type. Add abstract method comments
Merge master in improve-packet
Merge branch 'master' into improve-packet
Use factory pattern for creating packets
Add comments
Replace manual samples parsing with samples array.
Add none and empty frame checks
Merge master into packet branch

When possible, choose new packet code. However, we need to drop support
from some packets (notably node discover and node time).

Conflicts:
	automation/models/packet.py
	automation/models/sensor_reading.py
	automation/workers/frame_consumer.py