MailPoet 3 Class Conflict Issues

Hello,

I am unable to install MailPoet 3 due to class conflicts and looking at the source code the plugin will not work if it encounters common class names such as “Model” or “ORM” in the global scope. I think it would be a good idea to prefix or namespace the global class names in your plugin to avoid such conflicts as I think this could become a larger issue when more users switch to v3 from v2 in the future.