check headers

Сheck the headers in the request

We have identified a behaviour in nodejs/express. The headers names (keys) from the actual request come in lower case. We've got to handle it.
Eg.
```
function hasHeaders( httpReq, specReq ){
    if (!specReq || !specReq.headers){
        return true;
    }

    function containsHeader( header ){
        var httpReqHeader = header.name.toLowerCase();
        return (httpReq.headers && httpReq.headers[httpReqHeader] && header.value === httpReq.headers[httpReqHeader]);
    }
    return specReq.headers.every(containsHeader);
}
```