Draft: ENH: add plot_separate to dynesty trace plot
This MR adds the ability to specify certain parameters by name to plot in a separate trace plot. The idea is to do this for the calibration parameters in bilby_pipe eventually (addresses #672).
- Do people like the way this is currently done for dynesty?
- Can I get some help figuring out how to make the analogous change for bilby-mcmc?
- I still need to add unit tests.