add a test case demonstrating a memory-corruption bug
Add tracing support for the AIG and GIA interfaces
Fix a memory corruption bug in the GIA interface.
The code that adds and then deletes COs from a GIA
graph is quite fiddly; I am still not completely confident
that this code is correct, but it does fix the current issue.
Fix some silly parse errors and warnings
Fix a memory-corruption bug in the AIG interface.
The concrete evalator was failing to account for deleted vars,
which have NULL entries in the main object vector.