Update to 1.847
    
    - New upstream release 1.847
      - Obsolete RedHat MCE-Shared-1.841-Sereal-deps.patch file; this patch file is
        no longer needed and finally resolved with this release
      - Updated PDL examples in the documentation including Cookbook on GitHub:
        - Resolved segmentation fault in global cleanup for shared PDL objects
        - Added missing pdl_random class method to MCE::Shared
      - Bumped MCE dependency to 1.847