This should make it easier to run code on the physical MuSHR platform.

Allow linter to fail.
Add pipeline badge to each writeup to make grading easier.

Fix minor bug in resample test: the weights array had the wrong shape.

Add more motion model tests to identify turning issues.

Show particle filter plot legend to label state estimate vs ground truth.

Fix bugs in sensor model autograder tests. Specifically, the probability table
was being normalized along the wrong axis.

Add test suite for particle initializer. Add new tests to catch resampling
errors earlier.

Fix small issue in sensor model likelihood plot that affected some maps. Add new
small map to help with sensor model tuning.

Reduce excessive locking in particle filter, motion model, and sensor model.

Add new autograder tests to catch motion model errors earlier. In particular,
later particle filter tests will fail with a slow unvectorized motion model
implementation.

Update sensor model likelihood plot with a more interpretable default option
that only considers the particle positions (and doesn't encode their angle with
color). The option to color particles by angle is still available with
show_angle=True, and further emphasizes confident particles to make them more
visible.