retooling for hugo

Tweaking for Hugo
Updating the Dockerfile with new sed; fix broken link on Kitematic
Fixing image pull for Dockerfile
Removing docs targets

Signed-off-by: Mary Anthony <mary@docker.com>

docs/static_files/README.md

@@ -0,0 +1,11 @@
+Static files dir
+================
+
+Files you put in /sources/static_files/ will be copied to the web visible /_static/
+
+Be careful not to override pre-existing static files from the template.
+
+Generally, layout related files should go in the /theme directory.
+
+If you want to add images to your particular documentation page. Just put them next to
+your .rst source file and reference them relatively.