* NEWS: Mention the implementation
* python/spot/impl.i: Add dualize() to python interface.
* spot/twaalgos/Makefile.am: Add dualize.cc,hh to the build
* spot/twaalgos/dualize.cc: Implement dualize() that takes an automaton
and returns its dual
* spot/twaalgos/dualize.hh: Implement dualize()
* tests/Makefile.am: Add dualize tests to the test suite
* tests/python/dualize.py: Test cases for dualize
