Transifex should generate a template. A benefit of this is that it
automatically notifies about problems.
The file midori.pot does unfortunately have to live in the source
tree, but we remove it in clean and distclean targets.
Also three strings are marked untranslatable since they never
appear in the user interface and 'Unhandled settings value'
is reworded to 'Invalid configuration value'.
intltool automatically embeds comments in the po template
if they are directly before a translatable string. From
now on we will try to avoid leaving accidental comments
and instead put descriptive comments for translators
before strings, starting with 'i18n'.
