Bug during train

[xtuc]

./ba train --agent baagent --agent baagent --no-browser --tps 30 --port 8080 --agent baagent --agent baagent --agent baagent
  ├ version: dev (unspecified)
  └ Assertion error
    └ Failed to unmarshal incoming JSON in CommServer::Listen()
      ├ raw: [50 44 45 53 52 51 51 46 51 55 53 57 93 125 93 125 125 10 123 34 97 103 101 110 116 105 100 34 58 34 53 97 51 53 102 100 98 102 45 100 97 51 56 45 52 51 97 53 45 97 51 51 53 45 102 49 50 97 101 99 97 50 55 102 98 53 34 44 34 109 101 116 104 111 100 34 58 34 77 117 116 97 116 105 111 110 34 44 34 112 97 121 108 111 97 100 34 58 123 34 109 117 116 97 116 105 111 110 115 34 58 91 123 34 109 101 116 104 111 100 34 58 34 115 116 101 101 114 34 44 34 97 114 103 117 109 101]
      ├ string: "2,-5433.3759]}]}}
{"agentid":"5a35fdbf-da38-43a5-a335-f12aeca27fb5","method":"Mutation","payload":{"mutations":[{"method":"steer","argume"
      └ invalid character ',' after top-level value

[netgusto]

Tracked in #42