title: Colon character getting encoded to x003A in xml element serialization process
body: <p>I have defined type as Example as shown below, after instantiating a object and serializing using XmlSerializer, i am getting <code>x003A</code> instead of <code>colon :</code></p>
  
  <p>Here's my code:</p>
  
  <pre><code> public class Example
          {
              [XmlElement("Node1")]
              public string Node1 { get; set; }
              [XmlElement("rd:Node2")]
              public string Node2 { get; set; }
          }
  </code></pre>
  
  <p><strong>Serialization code</strong></p>
  
  <pre><code> Example example = new Example { Node1 = "value1", Node2 = "value2" };
  
              XmlSerializerNamespaces namespaceSerializer = new XmlSerializerNamespaces(); 
              namespaceSerializer.Add("rd", @"http://schemas.microsoft.com/SQLServer/reporting/reportdesigner");
              System.Xml.Serialization.XmlSerializer serializer = new System.Xml.Serialization.XmlSerializer(typeof(Example));
              string path = System.Windows.Forms.Application.StartupPath + "//example.xml";
              using (StreamWriter writer = new StreamWriter(path))
              {
                  serializer.Serialize(writer, example, namespaceSerializer);
              }
  </code></pre>
  
  <p><strong>Expected Result</strong></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;Example xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"&gt;
    &lt;Node1&gt;value1&lt;/Node1&gt;
    &lt;rd:Node2&gt;value2&lt;/rd:Node2&gt;
  &lt;/Example&gt;
  </code></pre>
  
  <p><strong>Actual Result:</strong></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;Example xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"&gt;
    &lt;Node1&gt;value1&lt;/Node1&gt;
    &lt;rd_x003A_Node2&gt;value2&lt;/rd_x003A_Node2&gt;
  &lt;/Example&gt;
  </code></pre>
  
  <p>Any help and direction in this are greatly appreciated. Thanks in advance!</p>