#675 Warn when redefining a core class

Originally at 2013-09-13T12:28:38Z by Damien Pollet I could define a Node class, which broke the environment. There was no warning or other hint that this name was already used in the system… Since it's such a generic name, prefixing Amber's Node could be useful too. <bountysource-plugin> --- Want to back this issue? **[Post a bounty on it!](https://www.bountysource.com/issues/7400884-warn-when-redefining-a-core-class?utm_campaign=plugin&utm_content=tracker%2F79201&utm_medium=issues&utm_source=github)** We accept bounties via [Bountysource](https://www.bountysource.com/?utm_campaign=plugin&utm_content=tracker%2F79201&utm_medium=issues&utm_source=github). </bountysource-plugin>