FE/Qt: language string updates.
FE/Qt: updated NLS prior to translation of 4.3.
FE/Qt4-NLS: merged ca, ca_VA, it, pt_BR
FE/Qt4-OSX: fix the translation of the application menu
FE/Qt4-NLS: merged ca, ca_VA, ja, zh_TW, nl, pl, it, bg, cs, ko and pt_BR
FE/Qt4-nls: merged Japanese, Slovak, Serbian, Danish, Spanish, Catalan (Valencian)