Overhaul the Visual Studio 2008 Projects

Split up the property sheets, so that they are easier to maintain, and
clean up the projects and property sheets, especially on items that are
being repeated, and therefore silence many build warnings.  Update the
project files correspondingly, and make all project files use Unix line
endings, for easier application of patches (the .sln and README.txt files
still has to have Windows line endings in order to work properly).

Also make the copying of config.h.win32 and clutter-config.h.win32(_GDK)
custom build rules, so that they may also be cleaned during the cleaning
of the build, which makes it easier for one to do a rebuild.

Similar updates to the Visual Studio 2010 project files will follow.
Overhaul the Visual Studio 2010 Build Files

Like the Visual Studio 2008 projects, give the Visual Studio 2010 projects
an overhaul, where:

-The property sheets are split up, so that they are easier to maintain and
 each project only needs to include the necessary parts.  The various
 projects are updated accordingly, too.  The copying of config.h.win32 and
 clutter-config.h.win32(_GDK) are now done with custom build rules, so that
 these files can be cleaned and/or recopied during a clean, rebuild or
 update.

-Clean up the property sheets, to get rid of parts that are actually
 repeated.  Also update the build macros, so that we won't get warnings
 for repeated #defines of macros and fix the build of the various tests/
 demo programs.

-Make all projects use Unix line endings, except for the .sln and
 README.txt files, which need to have Windows line endings.  This makes it
 easier to apply patches to these project files.

-Update the installation of headers, as headers are introduced/deprecated.

-Cosmetics: get rid of "\ No newline at end of file".
Visual Studio 2010 Projects: Add PlatformToolset Tag

This adds a PlatformToolset tag for each configuration so that it is easier
to upgrade the projects to Visual Studio 2012/2013 formats, which are
largely the same as the Visual Studio 2010 projects.  We can, for example,
use a script to change the values of the PlatformToolset to make these
projects usable out-of-the-box for Visual Studio 2012/2013.