many people no-longer install latex locally so getting set up can be tricky, use of latex shouldn't be hard-coded into beagle_utils.py

[eclake]

We should make pyp-beagle able to work without latex locally installed as it's a significant burden on setup - this would be possible from matplotlibrc file or within a script that later calls pyp-beagle, but unfortunately it's currently hard-coded into beagle_utils.