Status header is sent last

Status header is sent last to prevent header() from overwriting the ZF
status code when a Location header is used
Merge branch 'hotfix/3645'

Close #3645
Merge branch 'master' of git://github.com/fantasticjamieburns/zf2 into hotfix/3661
Merge branch 'hotfix/3661' into develop

Forward port #3661