title: Setting headers and http params for a single request in restangular
body: <p>I am trying to use restangular for file upload post request , I want to achieve the same functionality as below in restangular.
  However, I was unsure how to set content type and transformRequest for just this particular request. If I understand correctly, setDefaultHeader sets it for all subsequent requests. Is there some other way?</p>
  
  <pre><code>myApp.service('$fileUpload', ['$http', function ($http) {
     this.uploadFileToUrl = function(file, uploadUrl){
        var filedata = new FormData();
        filedata.append('file', file);
        $http.post(uploadUrl, filedata, {
           transformRequest: angular.identity,
           headers: {'Content-Type': undefined}
        })
        .success(function(){
        })
        .error(function(){
        });
       }
  }]);
  </code></pre>