README: improve formatting of important files

Previously, this entire block was in a script block.  This looked shitty:

![image](https://f.cloud.github.com/assets/23369/1935682/b8c2c7ca-7efc-11e3-9e0b-e0382cdd4bcd.png)

Now it's an unordered list (since it's an unordered list), and only the filenames are monospaced.  This sets them apart from the text describing them, making everything easier to read:

![image](https://f.cloud.github.com/assets/23369/1935686/c6fb71de-7efc-11e3-8e4b-95a2604b706f.png)