A lot of work on the presentation

The shell auto-image now runs code and turns the output into an image
that is embedded into the document

The prompt is configurable in /bin/prompt

The first draft is done up until the references section

shell/show-staging-area

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+cd /tmp/demo
+echo '$ git status'
+git -c color.ui=always status
+echo '$ git add greeting.py'
+git add greeting.py
+echo '$ git status'
+git -c color.ui=always status
+
+
+