use _illion.setset instead of illion.setset
divide test for _illion and illion, and add do_init in pysetset.cc to call initializer from subclasses
add constructor to illion.setset, and fix some bugs
fix a bug on pop() in pyset.cc
add object map in illion.py, still on the way...
remove setset_do_init in pysetset.cc by calling _illion.setset.__init__
add contains(), find(), not_find(), add(), remove(), discard() to illion.py
small modifications
make pysetset.cc compiled first
make setset_iterator accessible from python
make setset_iterator creatable from python
activate iterator in python, but it still has an error...