title: remove double linebreaks in string
body: <p>I am developing a asp.net web application, i have a string (with a value in it from a database), with multiple lines that i put in a TextBox with mulitline type. (textarea)</p>
  
  <p>Now the problem is, that in the string are multiple lines, with much empty space. so i want the remove only the double linebreaks.</p>
  
  <p>example of my textbox:</p>
  
  <p>+++++++++++++++++++++++++++++++++++++++++++++++++++++<br>
  {empty}<br>
  {empty}<br>
  'This is some text in the textbox on line 3<br>
  'some text on line 4<br>
  {empty}<br>
  'some text on line 6<br>
  {empty}<br>
  {empty}<br>
  'some text on line 9 <br>
  {empty}<br>
  +++++++++++++++++++++++++++++++++++++++++++++++++++++<br>
  now somehow i want to remove line 1 and 2, and line 7 and 8</p>
  
  <p>thanks in advance</p>