DOC: Add missing shapes in docstring

Addresses @antgonza's comment.

The previous commit also fixes #601 since there's no geometries are no
longer cubes.

emperor/support_files/js/shapes.js

@@ -13,8 +13,8 @@ define(['jquery', 'three', 'underscore'], function($, THREE, _) {
    *
    * Return a correctly sized geometry that matches the plotting space
    *
-   * @param {string} shapeName One of 'Sphere', 'Square', 'Cone', 'Icosahedron'
-   * or 'Cylinder'.
+   * @param {string} shapeName One of 'Sphere', 'Square', 'Cone',
+   * 'Icosahedron', 'Cylinder', 'Diamond' and 'Ring'.
    * @param {Object} ranges Object with two arrays of "max" and "min" values as
    * generated by the `DecompositionModel` dimensionRanges property
    *