made keys optional and return meta additionally

[sven09]

What is the purpose of this pull request?

made keys optional and return meta additionally

What problem is this solving?

• Be more flexible without knowing all columns of the csv or restricting to (e.g. use in NOSQL)
• Get the meta as additional result

How should this be manually tested?

As before

Screenshots or example usage

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Requires change to documentation, which has been updated accordingly.