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 #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.