Unable to change default headers #145

Hi,

One of the REST URL's response is json [Content-Type:application/json] but when i tried to overrride the default headers it doesn't reflect in the request headers -

resp, content = client.request(request_token_url, "GET",headers={'Content-Type':'application/json'})

headers={'content-type':'application/xml','Accept':'/','Connection':'keep-alive'}
cl.request(url,headers=headers)