Primitive lists

Primitive list implementation complete for JSON and XML. The XML format is shown in the last commit from this PR. This one depends on the JSON support PR, so once that one is in, there should be fewer commits showing up here. Unfortunately, the "Ignore compiled python bytecode" commit was on my master branch and I don't think I can get rid of it, so that one and its reversion are included here, which I don't think I can avoid, unless I want to exclude it from every branch I ever make for PRs.

I've since realized that the way to develop in this environment is to do all dev on a branch, issue the PR, then only put on master once the PR has been responded to, which is how I'll operate going forward.