Table formatting 

Some relevant links:
https://cran.r-project.org/web/packages/tables/vignettes/tables.pdf
https://cran.r-project.org/web/packages/tangram/index.html
https://gist.github.com/leeper/f9cfbe6bd185763762e126a4d8d7c286
http://haozhu233.github.io/kableExtra/awesome_table_in_pdf.pdf
https://github.com/haozhu233/kableExtra
