Round freqList and srcList 'pos' values to 2 decimal places.

[gofaster]

Occasionally, the "pos" keys' values in the "freqList" and "srcList" stanzas of the call metadata JSON file are presented to many decimal places.
This can occur when the binary representation of a floating point number is serialized. In this case, pos in T-R is a double; which has an approximate precision of 15 decimal places.
This change rounds the pos value to 2 decimal places, similar to what the OpenMHz uploader plugin does.

Example fragment from call metadata JSON:

...
  "freqList": [
    {
      "freq": 852550000,
      "time": 1769708284,
      "pos": 0.0,
      "len": 1.52,
      "error_count": 0,
      "spike_count": 0
    },
    {
      "freq": 852550000,
      "time": 1769708286,
      "pos": 1.52,
      "len": 9.52,
      "error_count": 0,
      "spike_count": 0
    },
    {
      "freq": 852550000,
      "time": 1769708298,
      "pos": 11.04,
      "len": 3.28,
      "error_count": 0,
      "spike_count": 0
    },
    {
      "freq": 852550000,
      "time": 1769708303,
      "pos": 14.320000000000003,
      "len": 2.16,
      "error_count": 0,
      "spike_count": 0
    },
    {
      "freq": 852550000,
      "time": 1769708307,
      "pos": 16.479999999999997,
      "len": 1.6,
      "error_count": 0,
      "spike_count": 0
    },
    {
      "freq": 852550000,
      "time": 1769708310,
      "pos": 18.08,
      "len": 10.16,
      "error_count": 0,
      "spike_count": 0
    },
    {
      "freq": 852550000,
      "time": 1769708321,
      "pos": 28.24,
      "len": 4.84,
      "error_count": 0,
      "spike_count": 0
    },
    {
      "freq": 852550000,
      "time": 1769708327,
      "pos": 33.08,
      "len": 1.4,
      "error_count": 0,
      "spike_count": 0
    }
  ],
  "srcList": [
    {
      "src": 1899003,
      "time": 1769708284,
      "pos": 0.0,
      "emergency": 0,
      "signal_system": "",
      "tag": ""
    },
    {
      "src": 45410,
      "time": 1769708286,
      "pos": 1.52,
      "emergency": 0,
      "signal_system": "",
      "tag": ""
    },
    {
      "src": 45410,
      "time": 1769708298,
      "pos": 11.04,
      "emergency": 0,
      "signal_system": "",
      "tag": ""
    },
    {
      "src": 45410,
      "time": 1769708303,
      "pos": 14.320000000000003,
      "emergency": 0,
      "signal_system": "",
      "tag": ""
    },
    {
      "src": 1899003,
      "time": 1769708307,
      "pos": 16.479999999999997,
      "emergency": 0,
      "signal_system": "",
      "tag": ""
    },
    {
      "src": 45410,
      "time": 1769708310,
      "pos": 18.08,
      "emergency": 0,
      "signal_system": "",
      "tag": ""
    },
    {
      "src": 45236,
      "time": 1769708321,
      "pos": 28.24,
      "emergency": 0,
      "signal_system": "",
      "tag": ""
    },
    {
      "src": 1899003,
      "time": 1769708327,
      "pos": 33.08,
      "emergency": 0,
      "signal_system": "",
      "tag": ""
    }
  ]
...

[robotastic]

Good call