sort_field name with capitalization problem

[arghc]

I have had a problem with date sorting for a while. I have finally figured out what is causing the issue. When your sort_field name is CamelText (or has any capitalization?), the result is exactly the same as if your sort_field does not exist. eg. sort_field: startDate bad, sort_field: startdate good.

I believe in generator/utils.rb in sort_get_post_data that the key = r_key.downcase.strip # Remove any erronious whitespace and convert to lower case line is the culprit. No idea, what else might be relying on that, so hopefully it will be an easy patch for someone with experience to make?