Comment 0 for bug 1401085

Calibre 2.12 running on Windows 7 SP1 Basic.

The command `calibredb list --for-machine` (with json output) ignores custom columns, yet they appear when --for-machine is not used.

For instance, I've got a custom column named 'edition' and call:

`calibredb list -w 10000 --for-machine --fields="title,formats,tags,*edition" --search="The Art of Watching Films"`
Normal output without --for-machine looks like:
id title formats tags *edition
10 The Art of Watching Films [D:\Books\Dennis Petrie\The Art of Watching Films (10)\The Art of Watching Films - Dennis Petrie.pdf] [] 8

`calibredb list -w 10000 --fields="title,formats,tags,*edition" --search="The Art of Watching Films"`
Output with --for-machine:
[
  {
    "formats": [
      "D:\\Non-fiction\\Dennis Petrie\\The Art of Watching Films (10)\\The Art of Watching Films - Dennis Petrie.pdf"
    ],
    "id": 10,
    "tags": [],
    "title": "The Art of Watching Films"
  }
]