for markdown (including pandoc's flavor), the column name for rownames can be empty

it is only reST that requires nonempty table header cells
it is the default in kable_mark()
forgot to update the tests
mentioning pander and ascii packages as alternative kable functions
Merge pull request #661 from daroczig/master

mentioning pander and ascii packages as alternative kable functions
roxygenize after #661
Improve scrolling behaviour of gWidgetsWWW2 notebook example
Merge pull request #662 from jranke/master

Improve scrolling behaviour of gWidgetsWWW2 notebook example
need to filter the authors; the CRAN page is not correct: http://cran.r-project.org/web/packages/knitr/citation.html
use the `@include` tag to prepare the upcoming changes in roxygen2 (Collate will be gone)

klutometis/roxygen#139
expose the code option and make it possible to generate the code chunk programmatically
add AsciiDoc and Textile to the reference card, and use smaller fontsize for the table
bump version
the default device is NULL in opts_chunk, which will be changed to pdf for LaTeX output, and png/svg for HTML output

this allows one to opts_chunk$set(dev) before knit(); previously, if you set dev=pdf before knitting an Rmd document, the device will be restored to png forcibly, which is bad when we want to convert markdown to LaTeX through pandoc
factor out the code to crop images to plot_crop(); we can use it separately later
document and export plot_crop()
add a fig.process option to post-process plots
a helper function is_windows()
do not reinvent shell() under Windows
change tidy=TRUE to tidy=FALSE!