This required some editing re. number of plural forms. Not exactly sure why
Kazakh still has one plural form there (contacted them for clarification).
Also, Manx (gv), Shan (shn), and Central Kurdish (ckb) languages aren't
supported by Transifex at the moment (contacted as well)...
Remove Belarusian (be@latin) as it was no longer present on Launchpad.
Add Welsh (cy).