Colormap not scaled to min/max of number of people that are available

[drinkablebreeze]

The AvailabilityViewer's colormap has its limits set at 0 and n, when it should be the minimum/maximum number of people that are available for any time slot. This is easiest to see on an example with lots of responses, where no times have all people unavailable or available. The colormap ends up being low-contrast, since it's not scaled to the true min and max of the data.

I believe this is because calculateAvailability sets the initial value of min and max to 0 and n respectively, when it should be the other way around.