copy the relevant portions of self into copy-object.
ok if it calls copy on sub-objects.
copy-inner < array > < t > < t > |
copy-inner < hash-table > < t > < t > |
copy-inner < list > < t > < t > |
copy-inner < standard-object > < t > < t > |
copy-inner < string > < t > < t > |
copy-inner < t > < t > < t > |