* PCursor -> Pointer_cursor / PointerCursor ?

	* remove List::List(element)

	* efficient copy cons for List

	* extend Interval

	* change String::pos

		s[s.pos('%')] == '%'

	would be nice

	* use template handle in handle.hh for strings.

	* Restricted cursor/list: make sublist from a list, and use rcursor
as if list is as big as the sublist.

	* move towards gnu or STL?

		parsestream.h
		vector.h