STRIP_HTML - removes html entities from an htm file
    S = STRIP_HTML(FILENAME) parses the file FILENAME and removes 
    the html entities, while the result is stored in S as a 
    cell array and written in file "FILENAME.TXT".
 
  Copyright 2011 Dimitrios Zeimpekis, Eugenia Maria Kontopoulou, 
                 Efstratios Gallopoulos