For some reason, we used "vc_x64_lib" as the output directory for the
libraries, but "vc_mswu_x64" as the output directory for the samples.
Place the arch suffix, i.e. "_x64" part, always after the compiler
prefix (possibly including version), for consistency with both the
library output directories and with MSBuild project files, as
build/msw/wx_setup.props uses $(wxCompilerPrefix)$(wxArchSuffix)_...
as wxIntRootDir value.
This basically removes the "adv" library, even though it's still
preserved for compatibility with user make/project files referring to
it.
It is done because the distinction between "adv" and "core" was never
really clear (e.g. why wxTreeCtrl was in core but wxTreeListCtrl in
adv?) and it prevented some core classes from using adv ones.
