[PATCH 0 of 3] Discourage localizers from commiting incredibly buggy translations

[timeless at mozdev.org]

I noticed that localiziers are relying on translation tools which do a really ba
d job of merging/recovering from changes.

This patch series introduces a checker.

There's also a separate set of fixes to reduce the number of identified issues (
mg pulled most of that in his i18n repo).
displaying [PATCH 1 of 3] check-po: Introduce check-po.py ...