Portuguese Translation

Just finshed the portuguese blockchain translation. This translation was made using the language.json file as base for the translations (since machine made portuguese translations are harder to understand than plain english sometimes) and portuguese.json as base for the commit, as requested at https://blockchain.info/wallet/translations

The bitcoin address for the bounty is: 1GQwoEwV6J7QNdgxQJV6do2Nmyd2NhbM6K

One remark is that we have two kinds of portuguese in the world, the european one (current flag on blockchain.info) and the brazilian one (flag not avaliable). This commit is for the Brazilian one, but since this language does not exist yet on the website it was merged into the original portuguese.json file until the new language is supported. 

In the future the brazilian portuguese json file can extend the original portuguese (that can extends the base language file) to avoid non-translated strings in english to appear.

Thanks for the hard work in the blockchain.info website and I hope you enjoy my work. Its my first time submitting code to github, please be gentle (Im a bit shy). Thanks again