Respect the capitalization

[danielo515]

Capitalization is usually important for header objects.
Request.js for example does not recognices authorization but it works with Authorization
Currently the output is always lowercase

Regards

[kesla]

Idk if it's "usually important" - this module has been around for a while without it being requested before.

I don't need capitalization and if we're going to respect capitalization I think it should be configurable, considering that the spec says headers should be case-insensetive. So if you're interested in contribution, feel free to open a pull request!

[danielo515]

Hello @kesla

I'm basing my guess on how requestjs which is some kind of nodejs standard behaves.
I'll agree that it should be configurable

[DmitryMyadzelets]

The RFC at section 4.2 says "Field names are case-insensitive".