Merge pull request #572 from Marzal/Marzal-hasArtwork

Remove hasArtwork leftovers

chapters/exampleComplex.json

@@ -11,8 +11,7 @@
     },
     {
       "startTime": 168,
-      "title": "Hearing Aids",
-      "hasArtwork": "chapter1.jpg"
+      "title": "Hearing Aids"
     },
     {
       "startTime": 260,

chapters/jsonChapters.md

@@ -158,8 +158,7 @@ chapter list, but allows for different artwork to be shown:
         },
         {
             "startTime": 168,
-            "title": "Hearing Aids",
-            "hasArtwork": "chapter1.jpg"
+            "title": "Hearing Aids"
         },
         {
             "startTime": 260,