Merging working changes into master#4

Merged

savageautomate merged 25 commits intomasterfrom

Aug 20, 2019

Commits on Aug 13, 2019

Commits on Aug 14, 2019

working on test harness integration
savageautomate
committed

Commits on Aug 15, 2019

PIGPIO lib: added I2C support;
savageautomate
committed

Commits on Aug 16, 2019

Commits on Aug 17, 2019

updated I2C interface for read() and write()
savageautomate
committed

Commits on Aug 18, 2019

updated I2C interface for readers R/W of 16-bit word values
savageautomate
committed
updates to I2C interface, added examples, etc.
savageautomate
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adding PIGPIO plugin project, refactoring Arduino Test Harness
savageautomate
committed