Versioning and branch work

[limefrogyank]

This repo is starting to get used so we need a way to track when problems and macros have been updated.

I'm setting version 1.0.0 as the starting point for now. I'm suggesting these guidelines for increasing the version number.

1. Any major breaking changes will require a version change for the 1st number.
2. New features and major bug fixes for the macros will cause the 2nd number to increase.
3. Any problem additions, edits, and minor changes to the macros will increase the 3rd number.
4. Typo fixes and similar edits don't need a version change.

Any new features and major macro work must be edited via branch or fork. For convenience and because I have been the only one working on macros, I've been committing to main, but that will stop other than for minor typo edits. I'm open to suggestions on other ways to do this, but without any other input, this is what I'll do.

FYI, please describe the main changes in the commit message. i.e. typo fix, issue reference

Anyone is free to create pull requests! I realize it can become a headache for casual users, but a quick way to make a typo change if you're NOT a regular maintainer is to:

1. Create a fork. Hit the Fork button on the main page.
2. Edit the file in your own fork. You'll know you're in your fork and not the main repo because the url will have your username instead of "WeBWorK-for-Chemistry".
3. Go to pull requests and make sure you click on the "compare across forks" link just under the page title.
4. WeBWorK-for-Chemistry fork goes in the left box and your username goes in the right box that is circled:
   
   4a. If you're using this guide to create a pull request, I'm assuming you're not that familiar with programming and git so these should just be problem typos, new problems, etc. It's ok to use the "main" branch in this case.
5. Click "Create Pull Request"!

That should be it! Maintainers will take a look at it to make sure it's not going to break anything and will approve the merge at some point. If there are some conflicts, maybe you're using an old fork that hasn't been updated. If you don't know what to do, I'd recommend deleting your fork and starting over.