added markdown
[go/en] add range index explication, and new learn source
Fix xml
Merge branch 'master' of github.com:daturkel/learnxinyminutes-docs into daturkel-master
Fixed up line lengths, and removed syntax highlighting because it sucked.
Merge pull request #606 from josedonizetti/golang_en

[go/en] add range index explication, and new learn source