Add translate until list comprehensions

I'm translating haskell guide from Adit Bhargava (learnxinyminutes contribuitor) but adding a few more stuff about haskell
Add traslate the topic more functions

Extra-Add a topic about the refs and 'keep readings'
Add translate until Haskell::IO

Plus some extra references
Change header contribuitor id to english labels
Add a complete translation on haskell guide

I have translated to brazilian portuguese your Haskell quick guide written by Adit Bhargava plus i have add some new ideas.
Add the contribuior and translator id's header

Just adding a better explained header
Merge pull request #420 from tonussi/master

[haskell/pt-br] PR: Learn Haskell Quick Guide Translated to PT-BR