We were hiding this under a toggle menu to reduce the page size of the hubs module. Now that each hub is on its own page, this is no longer necessary.
In turn, this makes it easier to document the same method for other hubs.
This renames the generic class from LightGrid to LightMatrix. The instance object is simply called display.
This makes user scripts easier to type and read.
This also cleans up most of the draft docstrings for this class and fixes a few argument typos.
Laurens Valk