Intellovations 003 Refactoring and Speed Improvements

[craigmaloney]

• thermostat/importers.py: Add multiprocessing support for importing up to three thermostats at a time

• thermostat/multiple.pyi: Add multiprocessing support for calculating EPA results on all available processors

• thermostat/importers.py: Update the equipment types to a structure (tuple)

• thermostat/core.py: Clean up exceptions to not be hidden in an else clause.

• thermostat/climate_zone.py: Split climate zone calculations into a separate method.

• thermostat/core.py: Add runtime option to output cached data to a file for each thermostat.

• thermostat/stats.py: Added core_mean_indoor/outdoor_temperature calculation

• thermostat/exporters.py: Add core mean temperatures to metrics

• setup.py: Update to version 1.4.0

• docs/api.rst docs/tutorial.rst: Added multiprocessing documentation

• scripts/tutorial.ipynb scripts/multi_thermostat_tutorial.py: Added examples for multiprocessing

• thermostat/multiple.py: Properly handle duplicate thermostat keys under multiprocessing

• tests/fixtures/thermostats.py tests/core.py: Added duplicate thermostat key regression test