gson.bindTag(ExternalInput.class, "name", "name");
gson.bindTag(ExternalInput.class, "description", "description");
gson.bindHandler(ToolState.class, new StateHandler());
gson.bindTag(Position.class, "unitsFromLeftMargin", "left");
gson.bindTag(Position.class, "unitsFromTopMargin", "top");
gson.bindTag(ExternalOutput.class, "name", "name");
gson.bindTag(ExternalOutput.class, "type", "type");