qt5 upgrade

This may need to be changed. When I was tinkering with Qt5 I had to use:

 Q_PLUGIN_METADATA(IID "org.xtuple.Plugin.CSVImpPluginInterface/0.4");

Which was what the interface was defined as, and what the Qt client looks for. I don't know enough to know why, just giving you a heads up in case you run into issues with the qtclient complaining it can't find the plugin.