This attempts to organize all needed items and places appropriate defines
in a single location. Redundant comparisons/defines were removed when noticed.
A few caveats, however:
* This may be better targeted towards the 5_1_0 branch instead of master right now.
* Cmake will run a little slower on configuration/generation now. That's due to the sanity checks it runs.
* There are some more checks to be added later, but this should be a solid start.
Thanks to the [libical](https://github.com/libical/libical) project for inspiration.
Previously, the PIUIO_Leds code logged every LightState of every PIUIO_Led light with every call of Set()
This commit adds checks to see if each of the PIUIO_Leds have changed LightState since the last Set() and skips logging the current LightState if there is no change. Each set of lights was already being looped through; the new code here just issues a continue to skip logging where possible.
This helps reduce CPU usage when PIUIO_Leds are in use as the LightsDriver.
The mappings in this driver are specific to the piuio kernel driver, but
once lights mapping is possible this could be made into a generic leds
class driver.
din