Update to support Django 1.9 ValuesIterable

[adonm]

Removes direct dependency on importing queryset which fixes Django 1.9 compatibilty

Related though, due to different way of retrieving fieldnames (as ValuesIterable is literally a queryset now) have just removed the ability to add verbose_names for all fields (just returning them for current model's fields), this could use some work

[kevin1024]

I'm running on this branch for my project and it's working for my purposes. So consider that a 👍 from me!

[andrewsmedina]

LGTM :)

[steventlamb]

Thanks for your submission, I am glad to see this branch is enabling some users to use django 1.9.

This branch removes some core features and cannot be merged as-is. In order to be considered, all unit tests must be made to pass.

One additional obstacle that may result from using values_qs[0].keys() is that dict.keys does not return keys in a deterministic order, which can cause undesired behavior in column ordering in the CSV.

[adonm]

ahk I'll have a look at this hopefully in next couple weeks when I get some time

[steventlamb]

Closed in favor of #82. Django 1.9 is supported as of https://github.com/azavea/django-queryset-csv/releases/tag/0.3.3.