title: Angular, content type is not being sent with $http
body: <p>Angular is not adding the correct content type option, I tried the following command:</p>
  
  <pre class="lang-js prettyprint-override"><code>$http({
      url: "http://localhost:8080/example/teste",
      dataType: "json",
      method: "POST",
      headers: {
          "Content-Type": "application/json"
      }
  }).success(function(response){
      $scope.response = response;
  }).error(function(error){
      $scope.error = error;
  });
  </code></pre>
  
  <p>The code above generates the following http request:</p>
  
  <pre><code>POST http://localhost:8080/example/teste HTTP/1.1
  Host: localhost:8080
  Connection: keep-alive
  Content-Length: 0
  Cache-Control: no-cache
  Pragma: no-cache
  Origin: http://localhost:8080
  User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.64 Safari/537.31
  Content-Type: application/xml
  Accept: application/json, text/plain, */*
  X-Requested-With: XMLHttpRequest
  Referer: http://localhost:8080/example/index
  Accept-Encoding: gzip,deflate,sdch
  Accept-Language: pt-BR,pt;q=0.8,en-US;q=0.6,en;q=0.4
  Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
  Cookie: JSESSIONID=C404CE2DA653136971DD1A3C3EB3725B
  </code></pre>
  
  <p>As you can see, instead of "application/json", the content type is "application/xml". Am I missing something here ?</p>