Additional Catch2 tests of existing functionality.

[jdeaton]

This PR is an extension of #60 and adds additional tests of existing MAST library capability. Most tests were originally implemented by @JohnDN90.

Below is a checklist of commits implemented by @JohnDN90 in his add_catch2_tests branch the whose contents/functionality need rolled in:

• [x] Added catch2 header file for upcoming new tests. (#60)
• [x] Bug fixes and enhancements to CMake files. (#60)
• [x] Added option to use libmesh_devel (development) version. (#60)
• [X] Added catch2 tests for some MAST base functions. (#60)
• [x] Added catch2 test for TEMPERATURE boundary condition. (this PR)
• [x] Added catch2 tests for mast_boundary_condition_base (this PR)
• [x] Removed shear coefficient (kappa) from isotropic material. Added plane strain support to isotropic material. (#60)
• [x] Added catch2 tests for mast_isotropic_material. (#60)
• [x] Multiple changes to orthotropic material, including added plane strain support. (#60)
• [x] Added catch2 tests for orthotropic_material_property_card. (#60)
• [x] Moved shear coefficient (kappa) to 2D section card and added overloaded functions to 2D section card. (#60)
• [x] Added catch2 tests for solid_2d_section_element_property_card. (this PR)
• [x] Added overloaded functions to isotropic 3D section property card. (this PR)
• [x] Added catch2 tests for isotropic_element_property_card_3D. (this PR)
• Added new public release statement to README.
• [x] Add overloaded functions to solid_1d_section_element_property_card. (this PR)
• Formatting for README.md
• [x] Multiple changes to 1d_solid_section_element_property_card. (this PR)
• [x] Added catch2 tests for solid_1d_section_element_property_card. (this PR)
• Added basic catch2 tests for generic 1D structural elements.
• Fixed bug in GitHub Issue #41 where NO_BENDING incorrectly called TIMOSHENKO.
• Added catch2 tests for 1D structural element with extension and torsion.
• [x] Fixed bug in GitHub issue #43, where incorrect I value was being used for bending about y-axis. (#75)
• Added many for tests for 1D structural 2-noded (edge2) element.
• Added generic catch2 tests for 2D structrual elements.
• Added many catch2 tests for 4-node quadrilaterial 2D element (quad4).
• [X] UPDATE EXAMPLES MOVING KAPPA FROM MATERIAL TO SECTION CARD (#60)
• [X] Fixed bugs in catch2 tests which caused some to fail when run with a debug version of MAST. (some fixed in this PR)

[jdeaton]

This PR has a good chunk of changes in it and completes the addition of tests for a lot of fundamental MAST infrastructure. The remaining commits begin to integrate tests of actual elements/Jacobians/etc. I think I will split this work and merge this in once CI clears and continue the test integration in another PR.