Add the installer, uninstaller, and generated docs

hooks/theme-set.sample

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+# This hook is called with the snake-cased name of the theme that has just been set.
+# To put it into use, remove .sample from the name.
+
+# Example: Show the name of the theme that was just set.
+# notify-send -u low "New theme" "Your new theme is $1"