fldb: Change JSON structure

From this (formatted to show the structure):

  {
    "files": [
      {
        "filename": "bash",
        "gitsum": "ab8f667a897e43cbbfe62ad77b7563dd18010b3d",
        "md5": "b81de36b3ef3bb64229833c055560c0f",
        "mtime": "2014-09-27T08:04:07Z",
        "perm": "0755",
        "sha1": "5bd4480674efa1614a1932d89eadc5a20274c66d",
        "sha256": "0b49e1823b1755722c683073dcfe1d5de865a40c42b3ac1f7c57aa35f27cca25",
        "size": 1021112
      },
      {
        "filename": "file1.txt",
        "gitsum": "83d0e7140acbc76f1667ac64e7e49f82463e50ef",
        "md5": "4d8fc0f2ea31fa798eee4431ab5216d0",
        "mtime": "2014-10-04T12:24:55Z",
        "perm": "0644",
        "sha1": "8a2385fbb557d2d046222b99bdc07a592ba0d1ba",
        "sha256": "759957b778b79ee8f098ddb9b94ce17e01467cc0444d218ca46f7ed9606e5d51",
        "size": 48
      }
    ]
  }

to this:

  {
    "files": {
      "bash": {
        "gitsum": "ab8f667a897e43cbbfe62ad77b7563dd18010b3d",
        "md5": "b81de36b3ef3bb64229833c055560c0f",
        "mtime": "2014-09-27T08:04:07Z",
        "perm": "0755",
        "sha1": "5bd4480674efa1614a1932d89eadc5a20274c66d",
        "sha256": "0b49e1823b1755722c683073dcfe1d5de865a40c42b3ac1f7c57aa35f27cca25",
        "size": 1021112
      },
      "file1.txt": {
        "gitsum": "83d0e7140acbc76f1667ac64e7e49f82463e50ef",
        "md5": "4d8fc0f2ea31fa798eee4431ab5216d0",
        "mtime": "2014-10-04T12:24:55Z",
        "perm": "0644",
        "sha1": "8a2385fbb557d2d046222b99bdc07a592ba0d1ba",
        "sha256": "759957b778b79ee8f098ddb9b94ce17e01467cc0444d218ca46f7ed9606e5d51",
        "size": 48
      }
    }
  }

50235390-4bc2-11e4-a997-c80aa9e67bbd