Filemeta json v4

New version of my implementation of being able to print out file-store metadata in json format. Now follows the json structure standard. Example output:
```
{
    "src_port": 54679,
    "event_type": "file-store",
    "proto": "TCP",
    "timestamp": "2014-10-18T23:26:24.080487",
    "src_ip": "1.1.1.1",
    "file-store": {
        "http": {
            "useragent": "<UserAgent>",
            "host": "unknown",
            "uri": "\\/***\\/******.zip",
            "filename": "***.zip"
        },
        "metadata": {
            "state": "closed",
            "size": "2082027",
            "magic": "Zip archive data, at least v1.0 to extract",
            "md5": "b102232d90943339fda144b818118cb6"
        }
    },
    "dest_ip": "2.2.2.2",
    "dest_port": 3128
}
```