Default plot sizes are too large

[benwhalley]

I'm not sure if this is unique to my setup but for me the default plot sizes when running code from within Rmarkdown are too large. This means the plot ends up cropped/scrolling within the element that is inserted.

After a little messing I've found that options(repr.plot.width=4, repr.plot.height=3) makes everything much more usable. Would it be worth setting a sensible default for this? Perhaps one which works when the user has a typical column width set?