ubirch lamps with new backend and signatures

This is the new release for lamps and sensors that does not require individualized code to work. The signature key is derived from the device itself.

Features:

• generic code
• sha512 hashed device ids
• sha512 payload signatures
• configurable device properties, via HTTP POST response
• 16 bit color range
• adaptive range, depending on environment
• improved sleep handling

To flash sensor and lamp:

• avrdude -c arduino -p m328p -P <usb-serial-device> -b 115200 -U flash:w:lights-sensor.hex
• avrdude -c arduino -p m328p -P <usb-serial-device> -b 115200 -U flash:w:lights-lamp.hex

Enjoy!