PSR + docs

* I changed everything to comply with PSR-2 standard
* I added PHPDocs to methods and attributes
* I've imported Wiki pages into the `docs` dir
* I've translated documentation to Brazilian Portuguese

As it breaks the API you may consider tagging as a new version.
`.DS_Store` git ignores should generally go in a global git ignore file: https://help.github.com/articles/ignoring-files#create-a-global-gitignore