Add a -q parameter to %rerun magic

[MatthewWilkes]

This allows the rerun magic to be run in quiet mode, which suppresses the === Executing: === and === Output: === headings as well as the text of the cell being re-run. This means that cells that print can optionally be re-run as part of a larger control structure like a loop without IPython-specific noise.

[MatthewWilkes]

I'm struggling to fix the sphinx build issue on Py3.7 here. I can't seem to build the docs locally, but I tried adding a newline to the options section as the output suggested to no effect.