Add memoize.identity function, which may be used to avoid long-lived POD copies.

git-svn-id: https://code.downthemall.net/repos/trunk@3622 43940e1f-b481-bb45-89eb-5c6a4bf3d40a
memoize.identify() some stuff that will likely contain copies

git-svn-id: https://code.downthemall.net/repos/trunk@3623 43940e1f-b481-bb45-89eb-5c6a4bf3d40a