This is necessary because:
- Transifex runs 'msgfmt -c' on any uploaded .po file
- pybabel adds a spurious '#~ msgid ""' to the end of some files
- 'msgfmt -c' ignores that this is commented out, and treats it
as a syntax error (clashing with the top file definition)
* Add Hebrew language flag (the flag of Israel)
* Update the language list (lang.html.full) to include Hebrew
* Use POT as a basis for yet untranslated files, instead of the Russian
translation files; this should also ensure Transifex doesn't report 100%
translations for these files, instead of 0%
* Update Hebrew translation of priority.po