Release/1.4.0 (#9)

* Intellovations 003 Refactoring and Speed Improvements

* 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

* Adding missing test file

tests/data/metadata_multiple_same_key.csv

@@ -0,0 +1,3 @@
+thermostat_id,equipment_type,zipcode,utc_offset,interval_data_filename
+8465829e-df0d-449e-97bf-96317c24dec3,1,62223,-7,thermostat_8465829e-df0d-449e-97bf-96317c24dec3.csv
+8465829e-df0d-449e-97bf-96317c24dec3,1,62223,-7,thermostat_8465829e-df0d-449e-97bf-96317c24dec3.csv