Finalize 0.9.1 (#1431)

* fix heading levels in user_guide/bifacial.rst

* whatsnew cleanup

* fix readme html

missing tag, maybe unicode zero-width spaces?

* readme: link to universal zenodo doi

* readme: update installation link for #1173

* whatsnew date

* additional contributors

* delete errant space

Add gallery example for modeling with interval averages (#1152)

* add example

* whatsnew

* fix title

* make plots more compact

* fix unrelated sphinx issue

* forgot this wasn't latex

* updates from review

Co-authored-by: Will Holmgren <[email protected]>

move ModelChain.weather and times to ModelChainResult (#1197)

* move ModelChain.weather and times to ModelChainResult

* stickler

* Update pvlib/tests/test_modelchain.py

Co-authored-by: Cliff Hansen <[email protected]>

* update docs

Co-authored-by: Cliff Hansen <[email protected]>

fix modelchain with module temperature and arrays (#1193)

* fix modelchain with module temperature and arrays

* refactor to directly build from arrays

* add test

* improve test

* fix test

fix run_model_from_effective_irradiance with iterable weather and exc…

…luding cell temperature (#1165)

* check for complete poa in _set_celltemp

* test for new location of ValueError, add test for run_from_eff_irrad with iterable of length 1

* handle single data/arrays, fix test

* remove old test

* add _verify_df to run_from_effective_irradiance

* remove ValueError from _set_celltemp

* test for single, list tuple

* edits from review

unwrap_single_value, validate_per_array in SingleAxisTracker.get_irra…

…diance (#1160)

* unwrap_single_value and validate_per_array in SingleAxisTracker.get_irradiance

* add test

* comment

refactor ModelChain inverter methods to use PVSystem.get_ac (#1150)

* deprecate methods

* remove new but unreleased methods

* refactor modelchain inverter methods for get_ac

* update whats new

* update api.rst

* remove tests for methods that no longer exist

* fix get_ac with sandia tests

* fix get_ac with sandia tests

* clean up pvsystem imports

* add test of infer_ac_model

* no v in deprecated args

* fix pull number....

* remove _infer_ac_model_multi

Add scale_voltage_current_power to ModelChain.pvwatts_dc (#1138)

* add scale_voltage_current_power to ModelChain.pvwatts_dc, docstring edits, whatsnew

* extend pvsystem.scale_voltage_current_power to not require all columns, and accept Series

* handle tuples, use temporary DataFrame

* improve scale_voltage_current_power, handle tuples

* sort the new test

* improve scale function, fix multiple string test

* multiple string test runs

* add PR number

* Maintain column order in returned DataFrame

Co-authored-by: Will Holmgren <[email protected]>

* whatsnew entry formatting

Co-authored-by: Will Holmgren <[email protected]>

Co-authored-by: Will Holmgren <[email protected]>

clean up 0.8.1 whatsnew (#1123)

* whatsnew cleanup

* add missing contributors

* backtick to apostrophe

* remove auto-merge artifact; set release date