Adds functionality for intersecting curved polygons

[kennyweiss]

Summary

• This PR is revamps and supersedes the code from @davidgunderman's PR #112, rebasing the feature/gunderman/bezier-polygon branch on our current develop branch
• It adds some functionality to primal's BezierCurve class to compute sector areas and centroid, where a sector is the region defined by a curve and the origin
• It add a CurvedPolygon class to primal. This encapsulates a polygon whose edges are BezierCurves
• It adds an operator to primal to find the interesection regions of a pair of CurvedPolygons. The intersection regions consists of zero or more CurvedPolygons.
• It adds comprehensive tests for all the new functionality
• It adds a preliminary example to quest to compute the overlap area between two high order MFEM meshes.

TODO:

• Improve high order intersection example.
  • [x] Make it easier to provide user input meshes
  • [x] Provide a means of outputting the intersection results. E.g. as an svg image
• [ ] Update RELEASE-NOTES
• [x] Perform thorough code review on intersect_polygon algorithm

[kennyweiss]

I added CLI11 support to make it easier to load different meshes and added a function to output the result as an SVG. Here is the default example (slightly tweaked for interpretability):

The source mesh is red; the target mesh is blue; and the intersection regions are green.

Here's another example of the two meshes shifted a bit from each other: Generated via:

>./examples/quest_high_order_remap_ex \
        --srcFile ../data/mfem/disc-nurbs.mesh --srcOffset -1.1 0 \
        --tgtFile ../data/mfem/disc-nurbs.mesh --tgtOffset 1.1 0

[kennyweiss]

The current code needs to be fixed for cases where the edges are exactly aligned. Here's what we get when the edges of the center box overlap:

Generated from:

>./examples/quest_high_order_remap_ex \
        --srcFile ../data/mfem/disc-nurbs.mesh --srcOffset -1 0 \
        --tgtFile ../data/mfem/disc-nurbs.mesh --tgtOffset 1 0