Sorry for the delay and my miss in further communication on this issue.
I would like to take this issue in two fronts for its closure.

1) Issue with headers .capitalize() vs .title()
2) Documenting the Interface

With respect to point 1), I assume that we all agree upon that headers
should stored in Titled-Format instead of Capitalized-format. 

So I went ahead with the implementation of Titled format with a
CaseInsensitive Lookup so that previous code using Capitalize format
would also return values from the headers dict.

John: I agree with your point that these changes would break the
.header_items() that returns a list of Titled() key-value pairs, whereas
the previous existing code would be expecting Capitalized key-value
pairs. CaseInsensitive Dict lookup would not solve it.

I had assumed that new code will be confirming to it and changed the
tests. Even though I thought about it, I did not bring it up for
discussion for backward compatibility header_items() method.

- I don't have a solution for how to make header_items() backward
compatible if we go for headers title() change. I shall try to come up
by today.

Now, if we go for a Case Normalization at the much later stage, will the
headers be stored still in capitalize() format? ( In that case, this bug
requests it be stored in .titled() format confirming to many practices)
Would you like to explain a bit more on that?


We can address the documentation of interface later to coming upon
conclusion on the first one.