* funcall with arbitrary number of parameters (now no more than 10)
* other way round: call perl from ecl - done - but need test & improvements
* document/test/use s, _s, create_string (or delete some of these)
* t_complex and other types
* spring package to existnce, e.g. like in Tcl::Tk, implement their
  'stringify' in terms of prin1 method
* transparent access to perl var from ecl, and for ecl vars from perl

