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!
roxygenize
play fire with crandalf: https://github.com/wch/r-source/commit/08814645839
wrap up fig.process into fig_process(), and change the meaning of x in hook_plot_foo()

x is just the filename now; c(basename, ext) was largely for the convenience of LaTeX \includegraphics{}
be explicit in fig_path()
use the latest version of roxygen2, with no wrap and no indent
065 is a better example; asked again -- closes #667
bump version