Fix "me" image on the about page

Add a section shortcode to enable wrapping a chunk of a post in a <section>
Add a section.flow class that removes grid from the section
Fix up the about styles so that the paragraph that Hugo wraps the <img> in behaves sensibly when floated
Fix the alt text in the circular_image shortcode

layouts/shortcodes/circular_image.html

@@ -1,7 +1,7 @@
 {{- $img := (.Page.Resources.GetMatch (.Get "name")) -}}
 {{- $id := .Get "id" -}}
 {{- $classes := .Get "class" -}}
-{{- $alt := .Get "alt" -}}
+{{- $alt := .Get "alt" | default $img.Params.alt -}}
 {{- $width := .Get "width" -}}
 {{- $resized_img := $img.Resize (printf "%dx%d" $width $width) -}}
 <img

layouts/shortcodes/section.html

@@ -0,0 +1,3 @@
+<section {{ with .Get "class" }}class="{{ . }}"{{ end }}>
+  {{ .Inner }}
+</section>