Spectral correction model upgrades

[mjprilliman]

Pull Request Template

Description

-Add new shared file for all things spectral correction
-Add two new spectral correction functions that take in precipitable water, clearsky index
-Incorporate into pvsamv1 (gui and sdk), pvwattsv8 (sdk only for now)
-Add precipitable water, clearsky ghi, dni, dhi as options in wfreader
-Add unit tests
-TODO: consolidate all air mass calculations to one function call, with same assumptions where appropriate (separate issue to be filed for patch)

Fixes #24

Corresponding branches and PRs:

Same branch of SAM, corresponding PR
rest develop

[ link any corresponding PRs in other repos, i.e. NREL/ssc#x ]

Unit Test Impact:

[ new tests written? ] Yes

[ expected changes in unit tests or speed of tests? ] Slight changes to Sandia and IEC61853 unit tests based on change in air mass modifier calculation assumptions (more changes to come in separate issue)

[ expected changes in test_results files? ]

Checklist

• [x ] requires help revision and I added that label
• [x ] adds, removes, modifies, or deletes variables in existing compute modules
• adds a new compute module
• [x ] changes defaults
• [x ] I've tagged this PR to a milestone

Reminders- this section can be deleted

[Checking for PySAM Incompatible API Changes]
(https://github.com/NREL/SAM/wiki/PySAM-Incompatible-API-Changes-&-Regenerating-PySAM-Files).

[When do the PySAM files need to be regenerated?]
(https://github.com/NREL/SAM/wiki/PySAM-Incompatible-API-Changes-&-Regenerating-PySAM-Files#when-do-the-pysam-files-need-to-be-regenerated-via-export_config)

[coveralls]

Coverage Report for CI Build 26894993287

Coverage increased (+0.007%) to 56.393%

Details

• Coverage increased (+0.007%) from the base build.
• Patch coverage: No coverable lines changed in this PR.
• 1369 coverage regressions across 19 files.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

1369 previously-covered lines in 19 files lost coverage.

Top 10 Files by Coverage Loss	Lines Losing Coverage	Coverage
ssc/shared/lib_iec61853.cpp	200	12.3%
ssc/shared/lib_weatherfile.cpp	195	45.63%
ssc/ssc/cmod_pvsamv1.cpp	173	87.16%
ssc/ssc/cmod_singleowner_heat.cpp	141	77.05%
ssc/shared/lib_irradproc.cpp	119	92.35%
ssc/shared/lib_cec6par.cpp	86	61.1%
ssc/ssc/cmod_pvwattsv8.cpp	78	82.88%
ssc/shared/lib_windfile.cpp	63	62.07%
ssc/ssc/cmod_singleowner.cpp	59	92.04%
ssc/ssc/cmod_pvwattsv7.cpp	56	85.14%

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Coverage Stats

Relevant Lines:	121845
Covered Lines:	68712
Line Coverage:	56.39%
Coverage Strength:	3454405.32 hits per line

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💛 - Coveralls