Add `update.sh` script

No use memorizing those commands and their parameters. This makes it
easier.
Add `init-docs.sh` script

Makes the initial steps just a tad easier.
Categorize `more` and `back` includes as snippets

Also, remember to actually call the CSS for these guys.
Add "back" button to "index_of" page

This will lead the users back to the main page of the site.