improve PT locales

Brazilian Portuguese:
- Singular form ends with "e" (`caractere`).

European Portuguese:
- Singular form has accent (`carácter`), while the plural one doesn't as these have different syllables.
    - Both carácter and caráter are valid orthography per AO-1990. I'm not sure which one is preferred for European Portuguese hence I've kept the form which was already being used, just added the lacking accent to it.

Reference: http://pt.wikipedia.org/wiki/Caractere