Clean up numbered lists in chapter 1 and 2

The last two items in chapter 2 had the same number. But instead of just
incrementing the last item, I've changed all lists to just use 1's. This
will allow markdown to handle the numbering automatically and make it
easier to add and rearrange items in the future.
Merge pull request #11 from watson/cleanup

Clean up numbered lists in chapter 1 and 2