Allow comment import

[mattip]

Now that #82 is merged, the only thing stopping me from importing a repo with ~4000 issues is the lack of support for comments. The api endpoint supports them, but it is not clear to me how to structure the csv file to have comments in them. Is that something you are interested in supporting?

[gavinr]

Yeah, it's hard to shove a comments JSON into CSV. My initial thought is to just put the comments array, i.e.:

[
    {
      "created_at": "2014-01-02T12:34:56Z",
      "body": "talk talk"
    }
  ]

Into a column in the CSV. Open to discussion though.

[DavidGriffith]

Is anything going on at all with this project?