Added support for semi-deep state copying and removed final qualifer on
performAction method to enable domains with large numbers of objects to
reduce memory overhead by only doing semi-deep copies of the modified
objects
imports
Merge branch 'testing' into semideepcopystates
Modifying ObjectInstance to only shallow coy on default. Modiying block dude test
Merge pull request #24 from jmacglashan/jmacglashan

Jmacglashan
Merge pull request #20 from jmacglashan/semideepcopystates

Support for semi-deep state copying;

I'm going to go ahead and merge this since I think it's safe.
forced domain to set its domain dependent flag to true if a relational attribute is added. Also added debug message that is printed when this occurs. Debug printing can also be silenced with the added method.