shlwapi: Test and fix the behaviour of the CopyTo method for file sizes not multiple of the internal buffer size, on SHCreateStreamOnFileEx-returned IStreams.

[David Quintana (gigaherz)]

Hello people,
I fixed Vincent's comment, and submitted the new version of the patch.
It has been quite a few days already so I'd like to know if there is
anything else left to do before the patch is looked at, or if there's
just too much going on at the moment, in which case I can re-submit
the patch in a few days/weeks, so that it can be looked at properly
when there's more time.

Vincent Povirk wrote:
> We should probably still exit the loop if fewer bytes were read than
> requested, rather than do another read at the end of the file.