Adding book picture, update theme

Added new book picture to the /Writing section. Also did some tweaks to
the themes so we can fine-tune some parts of the book list.

themes/sophie-lewis/assets/scss/main.scss

@@ -120,9 +120,17 @@ hr {
         padding-bottom: 1rem;
     }
     &.writing {
+        img {
+            margin-bottom: 0.75em;
+        }
+
+        .book-cell {
+            padding-right: 2em;
+        }
+
         .book-cover {
             float: left;
-            margin-right: 1rem;
+            width: 100%;
             text-align: center;
             img {
                 height: 184px;
@@ -142,6 +150,10 @@ hr {
                 background-color: #adadad;
             }
         }
+
+        .book-stats {
+            text-align: center;
+        }
     }
 }