Make the projects include a single property sheet as necessary, which will
in turn include the other property sheet(s) as needed, so that we can avoid
warnings where we include the same property sheets twice in a single
project.
Also make the copying of pre-configured headers into custom build rules so
that they can be removed upon the clean command from the IDE and that they
can be re-copied if their counterpart *.h.win32 are updated.
Like the Visual Studio 2008 project files, split up the property sheets
so to ease maintenace, and to prepare to use autotools to fill in the
header entries to "install".
Put some of the items that are frequently repeated in the projects as well,
also to simplify maintenance.
Also, update the autotools files to automate the upgrade of Visual Studio
2010 project as we now have multiple property sheets to copy and process.
