Enable the end users to disable sections of the postprocessor which they aren't using

[shardros]

Currently there is no way to disable things like writing the image to shepherd

[WillMunns]

I'm not sure we want to suggest this, it would make vision faster, but blind the arena and make debugging harder.

The write is currently into the tmpfs directory, so the benefit is probably smaller than you'd expect

[shardros]

Agree, vision is already fast enough.

The other thing which the post processor does which maybe we want to disable is the drawing of bounding boxes. Maybe for some situations it gets in the way of debugging. I'll let @WillMunns decide to close the issue if you want.