Improved and tidied up duplicate code for save version checking, so it now logs version or build and the error message simpler/clearer. Also made the logging of the load error (if it triggers the incompatibility message) a fatal error so log is more accurate.
git-svn-id: http://svn.uktrainsim.com/svn/openrails/trunk@2459 a9f3cfff-6c41-7446-b0ca-052bd761e6eb