add include_assets as argument to print method so that js/css assets can be included when using with knit2html
add more helper functions including open_notebook
remove printChart
assign temporary file in writeLines.
document fields for rChartsClass
add newline between chart and code div.
add support for Leaflet
fix nvd3 examples to use nPlot.
update Rickshaw class.
add legend, shelving and yAxis to Rickshaw template.
update gitignore
update leaflet assets.
bump version