Change Readme to Markdown #446

[TobiasNx]

Replace textile with markdown and add new headline and adjust other heading order.

[acka47]

+1

[fsteeg]

This needs a blank to be a header, but I don't think it makes much sense. I think you meant to add that as a new main header and moved all other header down one level. I think the levels and headers should remain as before.

[TobiasNx]

I reword the commit and adjusted the heading order in a new separate commit.

[fsteeg]

I still don't see how moving the headers one level down improves anything, but won't die on that hill.

Branches that are under review should not be force-pushed.

Updated two 404 links in 8fe1e31.

Switching to Markdown is great, so thanks for that.

[TobiasNx]

I am refering th the google markdown style guide with regard to the headings in the nwbib repo: hbz/nwbib#672 (comment)