Michael Doube

Anisotropy uses a similar `ExecutorService` approach to multithreading and includes a `shutdownAndAwaitTermination()` method that appears to clean up old threads. https://github.com/bonej-org/BoneJ2/blob/da5aa63cdc15516605e8dcb77458eb34b0f00b85/Modern/wrapperPlugins/src/main/java/org/bonej/wrapperPlugins/AnisotropyWrapper.java#L380 Fractal Dimension may be using a messy approach to...

Fixed by calling `shutdown()` on the `ExecutorService` in `net.imagej.ops.morphology.outline.Outline` and `net.imagej.ops.topology.BoxCount` 

PR #624 should be applied as well becuase it has a better threading model for `Outline`