Make plot labels mathtext-compatible
For the new plotting system based on Matplotlib, we want to avoid the call-out to "real LaTeX" by default, and use the approximate Mathtext system. I've grepped all the label text out of the
.plot files, and written a little script to try rendering them sequentially, found in
devtools (on a branch, soon to be merged to release-3-1-x). Currently we get crashes immediately...