Update to 1.812
    
    - New upstream release 1.812
      - Improved performance for MCE::Shared::Cache; this is now a hybrid LRU-plain
        cache implementation
      - Added parallel demonstration at the end of the documentation
      - Bumped MCE dependency to 1.814 for the example to run
      - Tweaked MCE::Shared::Ordhash and MCE::Shared::Server