i18n: import polib 0.6.4 (rev 84598f2b5365) This version fixes some upstream issues observed during the pt_BR translation update: #8 (obsolete entries reappearing); an unidentified issue that made i18n/posplit produce some spurious messages on the resulting po file; possibly others. These bugs probably didn't cause actual differences on the translated output, since an invalid message added to the .mo file wouldn't match an input message most of the time. But they do pollute the .po file contents (and diffs), adding some confusion to the translation process. db957a72fbd7, 4c50552fc9bc and 8ea51e9e7031 were included upstream, so the only remaining difference is the "no-check-code" marking.