Update to 1.993
    
    - New upstream release 1.993
      - Major rewrite of documentation, now in separate file
      - Rework error handling to distinguish between SSL errors and internal errors
        (like missing capabilities)
      - Fix handling of default_ca if given during the run of the program
        (Debian #750646)
      - util/analyze-ssl.pl - fix hostname check if SNI does not work