RenderersSettings: Turn VSync on by default if the user is not using Vista or later.

See #3049.
typo
cosmetics
VSFilter: move the AboutDlg version to a new define and use that
AboutDlg.cpp: use the MPC_VERSION_ARCH define
Reduce variable scope.
remove unneeded variable
run astyle
Improve contrib/sign.bat.

Check if Visual Studio is installed.