How to edit the wiki?

[dlesnoff]

@xflywind I used @yardanico's command to fetch all the MD files and add them to 
your repo. I'll write a script that retrieve all nim markdown code blocks and 
split them into a nbCode:. If no change has been made since you opened back the 
edit button, no links should have been compromised. Otherwise, I'll try to make 
a script to list all external links (that do not link to the wiki or 
www.nim-lang.org).