Radio packet decryption and latest data accessor

[adamclaassen]

Write something that takes a string input and puts it in a private Position class instance, with a public accessor. String is formatted as robotid,x,y,head,time. Ex: 1,1.234,5.678,2.398,123.234
The x and y coordinates are in meters and need to be converted to mm first. The heading can just be left alone.