Migrate to ADS1015 library for #11

[Gadgetoid]

1. [x] Must test for threading regressions, since the baked-in ADS1015 used a lock (added in #22) to ensure ADC reads don't clobber each other. ads1015-python will need to implement this. :warning: Do not regress #16 or #22 !!!
2. [ ] Should probably update to the new sn3218 codebase currently rotting in a private repository.
3. [x] Make sure ADC values are sensible and that things still work!
4. [ ] Test coverage leaves something to be desired

[coveralls]

Pull Request Test Coverage Report for Build 1712656816

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 82 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-5.7%) to 61.708%

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Files with Coverage Reduction	New Missed Lines	%
automationhat/init.py	82	58.93%
<!--	Total:	82		-->

Totals
Change from base Build 1439444397:	-5.7%
Covered Lines:	224
Relevant Lines:	363

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💛 - Coveralls