Do something about babashka classpath caching issues

[jacobobryant]

The default theme now uses babashka tasks. Occasionally when running a task, babashka gives a "could not find namespace" error for some reason. Running bb --force -e nil fixes it. It would be nice to prevent this from happening. As a workaround, we could also check to see if bb returns that error and then automatically run the --force command. This would be unideal because recomputing the classpath can be slow. But much better than having to go run the command manually.