circular detonation

[zingale]

PR summary

This is a new problem setup designed to test multidimensional shock detection.

PR motivation

PR checklist

• test suite needs to be run on this PR
• this PR will change answers in the test suite to more than roundoff level
• all newly-added functions have docstrings as per the coding conventions
• the CHANGES file has been updated, if appropriate
• if appropriate, this change is described in the docs

[zingale]

This now has inputs for 24, 12, 6, and 3 km and a plotting script for comparing. Here's a comparison of the temperature structure when run with shock burning disabled comparing 24 km and 3 km.