allow ```{.r} as the alternative syntax to ```{r} in R Markdown, per suggestion of @cboettig
fixes rstudio/rmarkdown#160: use the syntax `a &times; b^c^` for scientific notation in docx and markdown
use the new version of DataTables 1.10.2
docco will override the highlight css here
center images in HTML output
use formatR 1.0 and tidy_source()
bump the versions of evaluate and markdown
bump version