Portuguese (Brazil) Translation Contribution

[joaoguimaraens]

I want to contribute with a Portuguese (Brazil) translation—on values-pt/strings.xml file; there are some untranslated and mistranslated strings.

Let me know the best/recommended way to do this. If you can give me a branch creation permission, that should be enough, and you can do the PR creation and merge yourself whenever you want. (I don't want to fork this entire repository just to change one file, but I can do it if it's your preference.)

Also, all translation links on README.md are broken.