Translation update: Tutorial, The Unknown (All languages)

Updated with new script `development/translate_scenario`.
translate_scenario: Strip trailing newline from translation status
translate_scenario: Translate metadata

No comment about this code except that i was seriously considering to
--author someone else before committing.
translate_scenario: Py2.6 compatibility

Also make __file__ invocation more diff-safe.
translate_scenario: Hack to reuse old translation files

This should be reverted as soon as pootle is back and running.
translate_scenario: Note original scenario, add header to translated files
Add some old tutorial translations to po/scenarios/

Apparently those were not correctly imported by pootle, so let's try to
not lose data here. Refs 8a53acc.