title: Convert Words in a string to sentence case for german sentences
body: <p>I am searching for a way to change the words in a String to SentenceCase.
  I know the Method <code>TextInfo.ToTitleCase</code> but this is not working the right way for german. Like in the documentation of the Method:</p>
  
  <pre><code>Input                            Language    Expected result                   Actual result
  Per anhalter durch die Galaxis   German      Per Anhalter durch die Galaxis    Per Anhalter Durch Die Galaxis
  </code></pre>
  
  <p>Is there another way to convert this right (get the expected result)? The verbs and adjectives should be in lower case.</p>
  
  <p>There are a lot of question but I have not found one which is working the correct way with german.</p>
  
  <p><strong>edit:</strong></p>
  
  <p>I have tried</p>
  
  <pre><code>var ti = new CultureInfo("de-DE", false).TextInfo;
  var res = ti.ToTitleCase("Per anhalter durch die Galaxis");
  </code></pre>
  
  <p>res is know</p>
  
  <pre><code>Per Anhalter Durch Die Galaxis
  </code></pre>