 Usage:  addbutton(di, l_num, c_num, name, function)   
 
 Input:

  di                     Display 
                         
                         
  l_num                  integer, 1 ... count of lines of di 
                         
                         
  c_num                  integer, 1 ... count of columns of di 
                         
                         
  name                   string, the name for the new button 
                         
                         
  function               string, the name of the macro, which will be executeded on clicking the new button 
                         
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
