Adding brazilian localization and improving gitignore

Just added brazilian portuguese localization and improved gitignore. I noticed that the automatic locale detection was not working, so I made a little fix, check the diff for details.

I'm not sure if my fix suggestion is the best aproach for the project but at least it is working now, it detected my language and displayed text in portuguese.

I didn't alter anything tested, so I haven't changed test files.

Finally, I added .DS_Store, .Spotlight_V100 and Thumbs.db to .gitignore due to problems with these files in Windows and Macs.