Wrote and tested OpeningHoursValidatorTool. Not fully working, yet …

* Copied icons from https://github.com/ypid/opening_hours_map/tree/master/img
* Wrote gen_translations to convert translations from https://github.com/ypid/opening_hours.js/blob/master/js/i18n-resources.js
* Generated translations.

Open problems:

* pyopening_hours can not be imported?
* self.isTranslated = True causes crash without error message in the console.