Squashed 'libraries/i2cdevlib/' content from commit b6836bb

git-subtree-dir: libraries/i2cdevlib
git-subtree-split: b6836bb46e248574816356a6a0a589718b6949fa
Merge commit '6b6a07619a263f27bb80f61784416152ba015f16' as 'libraries/i2cdevlib'
Not sure what actually changed here, but these files seem worth having.