Improve random generation of values
Improve random generation of values

Create a random `unknown2` at start and use for remainder of session,
favor the last `course` when generating a new one, favor lower accuracy
values more, sometimes generate a float for accuracy, always have
`timestamp_ms_since_start` be greater than 5000 and simplify the
generation of other timestamps, randomly choose between 'network' and
'fused' for `loc.name` (favoring 'network'), don't have
`horizontal_accuracy` always match `accuracy`, refine most of the sensor
ranges.

bellowsj/aiopogo