better parameter names

svggen/library/Paperbot.yaml

 connections: {}
 interfaces: {}
-parameters: {battery: null, height: null, length: null, width: null}
+parameters: {battery_thickness: 4.9, wheel_radius: 25, robot_length: 83, battery_width: 60}
 subcomponents:
   paperbot:
     classname: ESPSeg
     kwargs: {}
     parameters:
-      battery: {parameter: battery}
-      height: {parameter: height}
-      length: {parameter: length}
-      width: {parameter: width}
+      battery: {parameter: battery_thickness}
+      height: {parameter: wheel_radius}
+      length: {parameter: robot_length}
+      width: {parameter: battery_width}