Order of an OrderedDict not preserved

[scraperdragon]

It would be nice if, when passing an OrderedDict to 'insert', the order of the columns was preserved: i.e.

>>> data = collections.OrderedDict([('A', 1), ('B', 2), ('C', 3), ('D', 4)])
>>> mytable.insert(data, ['A', 'B'])
>>> mytable.find_one()[-1:]
[1, 2, 3, 4]

(above from memory, sorry)

Obviously if OrderedDicts with different key orderings are provided, the database wouldn't be able to handle both orders, and should stick with the first.

I'll look deeper into this when I get a moment - was hoping to have a pull request sorted but it's a little more complicated than I expected.

[stefanw]

This should be fixed by 8f4cd59. Some set() operations were messing with order. Column keys are now treated as lists.