Add line offset headers

[emorydunn]

Useful for skipping rows in CSVs that have table titles

Description

This PR adds a header strategy to parse headers from the specified row number, ignoring any previous row (and fixes a few typos). The change is additive, leaving the existing .firstLine option in place. I've been using the the header strategy in of of my own apps without any issues.

The tests have been updated to include the new strategy by way of a table title, and all pass.

Checklist

The following list must only be fulfilled by code-changing PRs. If you are making changes on the documentation, ignore these.

• Include in-code documentation at the top of the property/function/structure/class (if necessary).
• Merge to develop.
• Add to existing tests or create new tests (if necessary).

[emorydunn]

@dehesa I just wanted to check in and see if there's anything else I need to do with the PR for it to be merged in. Thanks!

[dehesa]

Hi @emorydunn

First of all, I am very sorry I haven't looked into this 😔 My focus was on other projects and I didn't really noticed. I will check this week the PR and leave you some comments or accept it.

In any case, I highly appreciate you putting in the time to contribute here.

[dehesa]

Hey @emorydunn ,

Thank you for the contribution and the grammar changes. The PR looks good overall, I just left you some small comments. Also, please be sure to target the merge on the develop branch.

[emorydunn]

Thanks for taking the time to review everything. I updated the rowIndex in Reader.swift and think I found all of the indentation issues.

[dehesa]

Thanks for the changes @emorydunn. I just left a final comment.

[dehesa]

Done and, again, I am sorry it took so long.

[emorydunn]

Thanks, and don't worry about the timing, I'm happy to be able to contribute to a library I use so much