escape http headers to avoid HTTP header injection
escape http headers to avoid HTTP header injection

Change-Id: Id1c0bfded68b24b2ab16c95b3c1a8e71b9921afd
Reviewed-on: http://cr.qtquick.me/738
Tested-by: http://ci.qtquick.me/
Reviewed-by: Tasuku Suzuki <42980d970444f9101663582e70cd53623b3238b4@gmail.com>
Tested-by: Tasuku Suzuki <42980d970444f9101663582e70cd53623b3238b4@gmail.com>

qt-users-jp/qthttpserver,qt-users-jp/qthttpserver