curvilinear bits 'n pieces

[julesghub]

The additions for curvilinear mesh and solving. This PR includes code changes and examples.

Significant code changes in Python and C layer:

• Make an annulus Mesh, FeMesh_Annulus()
• Class for defining curvilinear dirichlet conditions, CurvilinearDirichletCondition. (More documentation needed)
• On every forceVector and stiffnessMatrix there is a rotMat memory chunk
• Method to immediately force a consistent coordinate system after solve
• Stokes solve aware of element rotation matrix, ALWAYS use _removeBCs=False

Examples:

• docs/examples/curvi_examples/ They include simple regression testing.

[jmansour]

Lets schedule a chat for next week to walk over this.

[julesghub]

See examples/curvi_examples for models in annulus geometry. To be merged into master release once the user interface is agreed upon by development team. @julesghub + @jmansour.

[rbeucher]

@julesghub do we want to merge this?

[rbeucher]

What do we want to do with this. It's been a while and we have not discussed it.

[julesghub]

I think we should aim to merge this code in. The interface isn't ideal but the functionality works and is part of Rohan and Thyagi's modeling. Happy to release 2.13 first and then add this functionality in thereafter.

[rbeucher]

Yes, I think we release 2.13 and then we merged into dev.