Test module for TiledWorkflow parallelization approach.

Has several levels of interface. Can be customized to do more.
Main interface idea is that it looks like grass.script.

Developed in 2016, likely superseded by combination of MultiModule and
ParallelModuleQueue.  Interface should be polished.
Very slow due to patching ("untiling"). Slower for single module calls
of a fast module like r.neighbors.