make new files validation go brrrr!

[spock]

closes #7

needs a review and some more testing, I have only tested the following:

• validating an empty, no-index dataset
• indexing a fresh dataset without any indices
• validating a freshly-indexed dataset

[laktak]

Thanks for your PR - I'll try to get back to you soon!

[laktak]

This looks good, thanks!

[laktak]

I moved the update parameter so we can keep the version at 3.