Merge pull request #39 from WISDEM/develop

Structural Damping Example and Code Linting

1. Structural damping prediction example for IEA 22 MW.
2. Code linting.
3. Outputs of matrix maps from sectional forces to stresses and strains (allows easy evaluation of stresses with Python after beam theory simulation).
4. Option to output SONATA matrices with applied rotation so that beam theory code sees zero twist for all sections. When called in the correct order, sectional maps to stresses and strains are also adjusted appropriately.
5. Improvements to Prony series viscoelastic materials and generation of 6x6 stiffness matrices for a Prony series beam implementation.
6. Bug fixes.

Merge pull request #23 from WISDEM/develop

Catching main up to develop with significant clean-up and additional testing.