importer: Add support for aged z database

[mafredri]

Had trouble importing my z database since my database has been been aged many, many times 😄.

So z uses aging which results in the db containing floats instead of ints:
https://github.com/rupa/z/blob/9d5a3fe0407101e2443499e4b95bca33f7a9a9ca/z.sh#L83-L84

This PR fixes the following error during import (jump import z):

err: strconv.ParseInt: parsing "2.9788732572612733": invalid syntax

I added a todo because I'm unsure what would be good / fair behavior. Rounding the values as-is to integers will give a slight advantage to results with a slightly lesser score (say, 22.2 vs 22.3 because both become 22).

I thought about multiplying with 100 to even it out a bit, but then I don't know what these scores would "mean" in jump.

[gsamokovarov]

Hey, thanks for fixing this!

When you're importing autojump or z scores, the best way would be to start from a clean slate, as the scores between autojump, z or jump are not really comparable. The "base" units weigh differently across the scoring algorithms and there is no need to try to normalize them. As long as the imported values are relative between themselves, all will be good and jump will take over the scoring with time.

So, if you see lot's of scores in your config that are close to each other, maybe boosting them a bit can help, but IMO, the rounding as done now will be just fine. You can remove the TODO and I'll merge it.

[mafredri]

No problem, it's a good code base so it was easy enough 😄.

Thanks for clarifying about the weights! I rebased away the todo 👍.

[gsamokovarov]

Thank you! 🙏