render tables full width, eg using github pages

[timotheecour]

cf https://stackoverflow.com/a/49471237/1426932

unless someone has a better solution

EDIT: some tables don't render well in github pages, eg: https://timotheecour.github.io/D_vs_nim/
also, not sure how to customize width

EDIT: in https://stackoverflow.com/a/49566642/1426932 i suggest using a chrome extension to make github full width

TODO: try https://stackoverflow.com/questions/49471020/how-can-i-change-the-rendered-width-of-a-github-readme-md/49566642#comment86297496_49471237