Nice tables

Makes the Chores List table prettier using the `tabularx` and `booktabs` packages, and the source code prettier by introducing a macro to add things to the list.

As a side note, we don't need to keep all the LaTeX-generated auxiliary files (`*.aux`, `*.bbl`, `*.blg`, and so forth) in git, especially since they change on every compile. I have deleted the existing aux files in this branch and added the   relevant file extensions to the `.gitignore` file so we don't have to worry about them any more.