Fix typo in customnode package javadoc

Author: ctrueden

src/main/javadoc/resources/customnode/package.html

@@ -52,7 +52,7 @@ <h3>If you only want to display some basic shapes</h3>
 
 
 <h3>More advanced meshes</h3>
-For this purpose, <code>ImageJ3DUniverse</code> has the method
+For this purpose, <code>Image3DUniverse</code> has the method
 {@link ij3d.Image3DUniverse#addCustomMesh Image3DUniverse.addCustomMesh(CustomMesh)}. 
 <code>CustomMesh</code> is an abstract base class, which is extended by
 <ul>