pulling buffer down to 1.5
oh type systems
[refactor] Better encapsulate dependencies

* Removed Context
* Created Heater to wrap hwio.Pin interactions
* Injected Heater/Thermometer into Thermostat
* Added a Thermostat.Run
* Removed /v1/thermometer
* Simplified /v1/thermostat response

These refactors should make the code much easier to start testing.