add gainlayers, levels, public_packet property object

add gainlayers, levels

_get_rt now private method.

public_packet now property object

__main__.py

@@ -4,8 +4,7 @@ from time import sleep
 def main():
     with vban_cmd.connect('potato', ip='ws.local') as vban:
         for i in range(100):
-            print(vban.strip[5].A1)
-            print(vban.strip[5].A2)
+            print(vban.bus[3].levels.all)
 
 if __name__ == '__main__':
     main()