Readme in RST format.

[philderbeast]

We render readme.md for a package. Could we also please render readme.rst?

ghc-plugs-out has a readme in this format.

[gbaz]

related: #574

Adding a rst parser/renderer to hackage is nontrivial. As with that issue, I'm disinclined to pursue this. Easier to just encourage people to use .txt or .md.

[philderbeast]

Would this be something we could have if we went with pandoc #565?

[gbaz]

we aren't going with pandoc. too many objections to the need to change the license as i understand it.