It's sometimes annoying that a csv.DictReader doesn't retain the field ordering given in the first line of the file. Sometimes it matters.

This patch converts the reader so that it returns an OrderedDict rather than a plain dict, thereby retaining the ordering.

All tests still pass (though I haven't yet added a test to verify that the field ordering *is* retained - didn't think it was worth it if the patch won't be added, but will happily add that test otherwise).

I have updated the documentation, but was unable in the time available to find out how to correctly reference the OrderedDict class so that it was correctly hyperlinked.