Update feature/gdas-validation with develop

[RussTreadon-NOAA]

Description
feature/gdas-validation is behind develop. This PR brings feature/gdas-validation up to date with develop

Resolves #685

Type of change

• Maintenance

How Has This Been Tested?
Install develop and forked feature/gdas-validation and run GSI ctests.

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• New and existing tests pass with my changes

[RussTreadon-NOAA]

@emilyhcliu , @ADCollard , and @CoryMartin-NOAA : Is this PR necessary? Are developers still using NOAA-EMC/GSI:feature/gdas-validation

[CoryMartin-NOAA]

I do think we need this branch, as there are some CRTM version changes (among others) to make the validation consistent

[RussTreadon-NOAA]

I do think we need this branch, as there are some CRTM version changes (among others) to make the validation consistent

I agree. We'll need to monitor commits to develop and decide if/when to merge updates into feature/gdas-validation.

[RussTreadon-NOAA]

Since this is a merge of approved changes from develop into a feature branch go ahead and squash merge changes in this PR into feature/gdas-validation.