Adding a "todo" list

There are lots of files with a rough structure from the syllabus but no content. I'd like to propose creating a "TODO" list of some fashion in the meta directory that lists these files (or in general, whatever work that needs to be done), along with an update to the procedure in the contributions file to request that the contributor update the list to reflect the changes they made.

I've made a first pass at creating this file (and updating the instructions) in this pull request.

Thanks,
Adam