Switch all project files (and designers) to Visual Studio 2010 versions. Code can now be compiled with VS2010, VS2012 and VS2013 (and Express versions) but not VS2008.
git-svn-id: http://svn.uktrainsim.com/svn/openrails/trunk@2242 a9f3cfff-6c41-7446-b0ca-052bd761e6eb