Made a few other little corrections too.
This is sloppy: after each ObjectWrap allocation the user needs to call ObjectWrap::InformV8ofAllocation(). In addition each class deriving from ObjectWrap needs to implement the virtual method size() which should return the size of the derived class. If I was better at C++ I could possibly make this less ugly. For now this is how it is. Memory usage looks much better after this commit.
this is awful. i'm sorry for being so messy.