Update to 1.814
    
    - New upstream release 1.814
      - Fixed an issue in regards to deeply sharing an array or hash
      - Replaced Sereal with Sereal::Decoder and Sereal::Encoder in Makefile,
        inside recommends section; ditto for META files
      - Revised limitations section in documentation, in regards to not having
        IO::FDPass, e.g. Condvar, Handle, and Queue
      - Added 'end' method to MCE::Shared::Queue
      - Updated documentation on dequeue and pending
      - Bumped MCE dependency to 1.818