PtrToStringChars v2 remix

A while back, in order to get some code to compile, I had to update PtrToStringChars
(found in vcclr.h) to work in the new Whidbey C++.

In case anyone wants this, I've posted my implementation (and a small main() to drive
it) here:

Keep in mind: this is my personal implementation, and not necessarily the same one
that will be shipped with Whidbey.  However, if you're looking for a solution,
it should work for you.