title: Trouble with CSV-Helper not converting bool values
body: <p>I'm starting to use <a href="http://joshclose.github.io/CsvHelper/" rel="noreferrer">CSV Helper</a> - an excellent little helper for your daily work - great stuff!</p>
  
  <p>One item I'm struggling with right now are <em>class maps</em> - I have a little class</p>
  
  <pre><code>public class SimpleClass
  {
      public int ID { get; set; }
      public string Name { get; set; }
      public decimal Percentage { get; set; }
      public bool IsValid { get; set; }
  }
  </code></pre>
  
  <p>and for exporting to CSV, I would like to replace the <code>IsValid</code> values <code>true</code> with <code>yes</code>, <code>False</code> with <code>no</code>; for that purpose, I've created a class map:</p>
  
  <pre><code>public class SimpleClassMap : CsvClassMap&lt;SimpleClass&gt;
  {
      public override void CreateMap()
      {
          Map(x =&gt; x.ID).Index(0);
          Map(x =&gt; x.Name).Index(1);
          Map(x =&gt; x.Percentage).Index(2);
          Map(x =&gt; x.IsValid).Index(3)
                             .TypeConverterOption(true, "yes")
                             .TypeConverterOption(false, "no");
      }
  }
  </code></pre>
  
  <p>and now when exporting my data, I'm using that class map:</p>
  
  <pre><code>CsvConfiguration config = new CsvConfiguration { Delimiter = ";", HasHeaderRecord = false, Quote = '"' };
  config.RegisterClassMap&lt;SimpleClassMap&gt;();
  
  using (MemoryStream stm = new MemoryStream())
  using (var streamWriter = new StreamWriter(stm))
  using (var csvWriter = new CsvWriter(streamWriter, config))
  {
      csvWriter.WriteRecords(list);
      streamWriter.Flush();
  }
  </code></pre>
  
  <p>Unfortunately, when I inspect what has been written, I see that I still get <code>True</code> or <code>False</code> - not the <code>yes</code> or <code>no</code> as I had hoped.....</p>
  
  <p>What am I missing here? I'm using CSV-Helper v2.5, installed from NuGet, and .NET 4.0 / Visual Studio 2010.</p>