Pin column headers in matrix during scroll

[triplingual]

It would be nice if the column headers in the cookbook matrix would stay fixed as one scrolls down the page so a visitor doesn't have to memorize the headers as they scroll down. May be increasingly useful as we start to look at bringing 3D viewers into the matrix.

[regisrob]

It would be a useful improvement indeed. And having colors for YES and NO would make the table even more clear and readable (green for YES and red for NO)

[triplingual]

Not green/red, though, as that is not good for the red/green colorblind among us (as high as 10% of men in some populations). But yes, fundamentally that would be good.

[glenrobson]

Fixed in #524