Support beautification of HTTP 100 responses.

[jparise]

Detect when the server sends an HTTP 100 (Continue) response header
and kick our beautification loop into 'continuing' mode. While in
this mode, we wait for another ^HTTP/ header to be received before
responding to the \r\n break sequence signalling the end of the
headers and the start of the body. This gives us output like:

HTTP/1.1 100 (Continue)

HTTP/1.1 200 OK
Content-Length: 387
Content-Type: application/json; charset=UTF-8

{
}

This comes into play when uploading files using curlish.

Previously, these types of HTTP conversations were not "beautified"
because the header processing loop bailed out after the initial
HTTP/1.1 100 (Continue)\r\n\r\n content was handled.

[mitsuhiko]

I will apply this. I wonder though it it makes sense to match for HTTP/\d+\.\d+\s+100 instead of just one space.

[jparise]

That's probably a good improvement. The same would apply to the existing HTTP/\d+.\d+ [45]\d+ test, as well.

[jparise]

@mitsuhiko, would you consider merging this for a future release?

[mitsuhiko]

Yes, will do that. Just have to check that it works :)