Strings translations

Copied the strings.xml file to an html file and sent to Duolingo. Here
is the crowd sourced translations for the Spanish and Portuguese strings
files.  German, French, and Italian translations (hopefully) pending.


I'm new to this whole Git thing, so if I'm doing something wrong can you let me know? Also I'm not sure if the _pt language tag is correct, or if it needs to be country-specific (_pt-BR for example)

I'll update these translations as they are checked and rechecked by duolingo users.