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.