title: C# base64 encoding/decoding with serialization of objects issue
body: <p>I'm using serialization and deserialization in C# for my Project (which is a Class).
  They are serialized and saved to an XML file. When loading the Project, all goes well.</p>
  
  <p>Now I'm trying to encode the serialized Project to Base64 and then save the file, which goes well too. The first line of the file (before encoded!) looks like this:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
    &lt;Project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"&gt;
  </code></pre>
  
  <p>When I decode the file, there's a <em>?</em> added in front of the line:</p>
  
  <pre><code>?&lt;?xml version="1.0" encoding="utf-8"?&gt;
    &lt;Project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"&gt;
  </code></pre>
  
  <p>The code I use to encode:</p>
  
  <pre><code>byte[] toEncodeAsBytes = System.Text.ASCIIEncoding.ASCII.GetBytes(toEncode);
          string returnValue = System.Convert.ToBase64String(toEncodeAsBytes);
          return returnValue;
  </code></pre>
  
  <p>And the code for decoding:</p>
  
  <pre><code>byte[] encodedDataAsBytes = System.Convert.FromBase64String(encodedData);
          string returnValue = System.Text.ASCIIEncoding.ASCII.GetString(encodedDataAsBytes);
          return returnValue;
  </code></pre>
  
  <p>What can this be and how can I fix this? </p>