htmldoc : 
  generate the .book
  grep '<a href="' ../helios_bt/classes/index-helios_bt.html | sed 's,<a href=",../helios_bt/classes/,g' | sed 's/.html.*/.html/g'
  grep '<a href="' ../helios_bt/objectproperties/index-helios_bt.html | sed 's,<a href=",../helios_bt/objectproperties/,g' | sed 's/.html.*/.html/g' >>book.book
 grep '<a href="' ../helios_bt/dataproperties/index-helios_bt.html | sed 's,<a href=",../helios_bt/dataproperties/,g' | sed 's/.html.*/.html/g' >>book.book
cd into the dir and run :
   $ htmldoc --batch book.book