Enable the object-shorthand ESLint rule in src/shared

Please see http://eslint.org/docs/rules/object-shorthand.

For the most part, these changes are of the search-and-replace kind, and the previously enabled `no-undef` rule should complement the tests in helping ensure that no stupid errors crept into to the patch.

src/core/pattern.js

@@ -394,7 +394,7 @@ Shadings.Mesh = (function MeshClosure() {
       type: 'lattice',
       coords: new Int32Array(ps),
       colors: new Int32Array(ps),
-      verticesPerRow: verticesPerRow
+      verticesPerRow,
     });
   }
 
@@ -501,7 +501,7 @@ Shadings.Mesh = (function MeshClosure() {
       type: 'lattice',
       coords: figureCoords,
       colors: figureColors,
-      verticesPerRow: verticesPerRow
+      verticesPerRow,
     };
   }