JiaxiangBU/add2ggplot: add2ggplot 0.3.0

Jiaxiang Li
Add cran badge. Fix image path, update disclaimer, update readme framework. Fix the invalid url https://en.wikipedia.org/wiki/w._E._B._Du_bois Update the year of the license. Use 'donttest' instead of 'dontrun' into the functions. Add '@return' into the function metadata. Add examples for all exported functions. Add depends for some functions. Move used files into 'inst/extdata'. Add code of conduct Fix invalid urls. Fix mis-spelling. Drop invalid urls. Fix title in the tite case. Add cran comments. Added the...
This data repository is not currently reporting usage information. For information on how your repository can submit usage information, please see our documentation.