Monitor JSON change

The new code will still output the old format if you run 'burp -a m' with an old burp client (<= 2.1.8). I have also added an option to the monitor to override to a particular peer version, if you need to. So, you can just enter
'j:peer_version=2.1.8' to get the old format.

There is a new section called 'children', into which the "counters" and "phase" sections have moved.

{
    "clients": [
        {
             "name": "testclient",
             "run_status": "running",
             "protocol": 1,
             "children": [
                 {
                     "pid": 3943,
                     "backup": 4,
                     "phase": "backup",
                     "counters": [
                         {
                             "name": "files",
                             "type": "f",
                             "count": 0,
                             "changed": 0,
                             "same": 0,
                             "deleted": 0,
                             "scanned": 16
                         },
                         {
                             "name": "directories",
                             "type": "d",
                             "count": 0,
                             "changed": 0,
                             "same": 0,
                             "deleted": 0,
                             "scanned": 1
                         },
                         {
                             "name": "grand_total",
                             "type": "Z",
                             "count": 0,
                             "changed": 0,
                             "same": 0,
                             "deleted": 0,
                             "scanned": 17
                         },
                         {
                             "name": "bytes_estimated",
                             "type": "G",
                             "count": 420151988
                         },
                         {
                             "name": "time_start",
                             "type": "b",
                             "count": 1495345509
                         },
                         {
                             "name": "time_end",
                             "type": "E",
                             "count": 1495345510
                         }
                     ]
                }
            ]
        }
    ]
}