advpack: Prepare the unicodification of advpack.dll.

advpack: Prepare the unicodification of advpack.dll.
All functions that manipulate strings should have an Ansi and a
Unicode variant.
Forward the unqualified dll entry points to the Ansi variant for
backward compatibility.
We're not allowed to use unqualified entry points in Wine, so change
RegInstall() calls to RegInstallA().
Update win32.api.