Added GaussianDistribution Tests (#3221)

* Added GaussianDistribution Test.

* Removed unused method and added test for exception.

* Changed comment.

* Added Area3DTests.cpp (#3216)

* Added BasisFunctionTests.cpp. Removed BasisFunction unit test and truthfile.

* changed expectedOutput values for some of the tests

* Made tests for Displacement.cpp using gtest. removed Displacement unitTest and truthfile.

* Added Area3DTests.cpp, removed Area3D truthfile and unit test.

* included TestUtilities.h for use with exception testing, added a test for teh Area3D '=' operator

* changed formatting to adhere to USGS coding standards

* re-addedd the unit test and truth file

* gllssi2isis Original Label Fix (#3226)

* Allowed writting of residuals when value is zero to controlnet pvl

* Updated ControlNetVersioner unit test

* Fixed pvl labels original pvl labels not being written to the resulting cube.

* Updated docstrings and history for updated methods

* Removed the need to set the output cube pixel type

* Reverted proceeimport changes

* Set the dimensions in the process before processing

* Added missing 1 in a history record

* Reverted and applied a more appropriate fix

* Used outfile obtained at the beginning of the program

* Added history comment to app xml

* Removed accidental comma (#3230)

* Update README.md (#3232)

Update readability

* Modifying files for conda build for ISIS3.7.0_RC2 (#3229)

* Modifying files for conda build for ISIS3.7.0_RC_2

* Changes to modifications until issue #3231 can be completed

* Small typo

* One final added comment for clarification

* Adding tab completion for tcsh on conda activation (#3244)

* Modifying meta.yaml and version files for ISIS3.7.0 Public Release (#3254)

* Modifying meta.yaml and version files for ISIS3.7.0 Public Release

* Fixing date on version file

* Put the Probability method back and removed the old unit test and truth data.