Ordered list displays with bullets instead of numbers

[rouson]

@m3rabb if you have a moment to checkout the numbered-list branch, I bet this is a problem you can help us resolve pretty easily:

The following static HTML displays as a numbered list in Chrome:

1. foo
2. bar

When we generate a list with the same tags in the createCourseElement function inside src/main.js, we get bullets instead of numbers. (See https://github.com/rouson/classroom-randomizer/blob/numbered-list/src/main.js#L13.)