suppress warning from rgl
cosmetic changes in R HTML
cosmetic changes of line breaks
the highlight engine no longer uses alltt for other languages
wow, R knows how many objects are masked now
use T1 font encoding to avoid possible weirdness like <> being weird symbols, which may puzzle LaTeX beginners

thanks to Duncan Murdoch
use fontenc
use the subcaption package instead of subfig; closes yihui/knitr#619
wrap text
make