Header Names Are Not Case-Sensitive!

[dnwiebe]

The HTTP standard states that HTTP header names are not case-sensitive. Therefore, Host, host, and HOST all mean the same thing.

However, in HttpProtocolPack, in the find_header_host() function, only Host is accepted: any other casing will be ignored. This is potentially a big problem, because I know of clients that only ever use all-lowercase header names.

Drive case-insensitivity into find_header_host(), and find any other places in the code where we're seeking header names in a case-sensitive manner: change them too.

[kauri-hero]

Could be causing problems when trying to connect to certain servers
browser doesn't have control about that