Signaling - LED and Multi Color Led Refactor

[stevenj]

My Target doesn't have any leds. It has a buzzer. So i added code to drive the buzzer, instead of a LED. But in the process I found the existing LED/Multi Color LED code is quite difficult to discern and is spread all over the place. So I refactored it, and created a new signal module to manage signalling. It can handle the RGB Leds, single flashing leds and also a piezo buzzer on a TCC. I am still testing this code, so this pull request is for review and comment before I finish it.

However, its a lot simpler than the old code, and a lot more flexible. It allows different pulse streams on leds and buzzers to be easily added for different status indications, without using much code. In fact, i built every target using this new signal handling and they are all smaller than before, sometimes significantly smaller:

board	original size	free	new size	free
circuitplay_m0	7412	320	7224	512
dadamachines-automat	7256	476	7232	504
eitech-robotics	7244	488	7220	516
feather_m0	7384	348	7224	512
feather_m4	8772	7148	8608	7316
gemma_m0	7412	320	7408	328
generic	7244	488	7220	516
grove-zero	7260	472	7232	504
itsybitsy_m0	7432	300	7436	300
metro_m0	7400	332	7224	512
metro_m4	8780	7140	8620	7304
metro_m4_revb	8776	7144	8612	7312
mkr1000	7256	476	7228	508
pirkey	7388	344	7392	344
sensebox-mcu	7248	484	7224	512
sparkfun-samd21-dev	7284	448	7260	476
sparkfun-samd21-mini	7288	444	7260	476
trinket_m0	7416	316	7412	324
wattuino-rc	7264	468	7236	500
zero	7244	488	7220	516
Controleo3 (using buzzer)	???	???	7300	436

I haven't got any of these boards, so if anyone would like to help me test the various configurations (the two RGB leds that are defined, and M4 boards, and boards with single leds) I would really appreciate it. Also, the flash timings at the moment are arbitrary, so if anyone has a better scheme to suggest for on/off times for various states, let me know.

[mmoskal]

@dhalbert would you be willing to take a look?

[dhalbert]

Sure, happy to test. I'll try it on Adafruit boards, and I have an Arduino Zero.