Add second usage example for extending Value with attributes - closes https://github.com/scala/bug/issues/4803 - see also https://stackoverflow.com/a/6546480
Add second usage example for extending Value with attributes
- closes https://github.com/scala/bug/issues/4803
- see also https://stackoverflow.com/a/6546480

additionally:
Drop wrapping of the existing example in `object Main extends App`
Add comment to existing example

lrytz/scala,martijnhoekstra/scala,scala/scala,lrytz/scala,lrytz/scala,martijnhoekstra/scala,martijnhoekstra/scala,martijnhoekstra/scala,martijnhoekstra/scala,lrytz/scala,scala/scala,lrytz/scala,scala/scala,martijnhoekstra/scala,scala/scala,lrytz/scala,scala/scala,scala/scala