Updated support for YAML files

Today’s update brings a new parser for YAML files that:

• is faster.
• handles correctly some edge cases of YAML syntax the previous one had issues with.
• removes untranslated entries from downloaded translation files, when they are downloaded to be used in the user’s program instead of for offline translation by translators.

All new resources for YAML files will automatically use the new parser; existing ones will keep using the previous one.

Since the previous parser is now deprecated and will be removed in two months, existing resources will have to be migrated to the new parser. We have already contacted the maintainers of projects with YAML resources with instructions on how to perform the migration.