Response builder broke header value

[snapshotpl]

Q	A
Bug?	yes
New Feature?	no
Version	1.2.0

Actual Behavior

Curl client (and maybe more) using Http\Message\Builder\ResponseBuilder. When client adds Content-Type: application/hal+json header using addHeader method, created response contains Content-Type: application/hal json

Expected Behavior

Created response should contains valid header value as it's in raw response.

Steps to Reproduce

Send request to get response with header contains + eg. Content-Type: application/hal+json

Possible Solutions

Remove / fix decoding in https://github.com/php-http/message/blob/master/src/Builder/ResponseBuilder.php#L139

[sagikazarmark]

@snapshotpl sorry for not answering earlier. Just for you to know, this issue is being taken care of.