Update to 3.3.50
    
    - New upstream release 3.3.50
      - Limit number of rows that can be displayed in mouseover in order to
        prevent potential X11 crashes on extremely wide signals
      - Added "/File/Grab To File" PNG image grab menu option
      - Added missing $dumpvars emission in fst2vcd
      - Added missing atto and zepto time prefix parsing in vcd2fst
      - Added VHDL package type to FST
      - Added red box around 'U' vector values for VHDL similar to 'X' for Verilog
      - Used FST "attribute name" for variable types if specified
      - CRLF fix for save file reading on LF-only systems
      - Fix Valgrind hit in fst.c that was causing crashes on OSX
      - Added fstWriterSetFiletype() and fstReaderGetFiletype() to provide sim
        language hint to gtkwave for language-appropriate formatting of various
        data
      - Added fstWriterSetSourceStem() so writers can embed source stems in the FST
        file (specify before the appropriate hierarchy or variable declaration)
      - Added gtkwave_bin_launcher.sh script to set up environment variables on OSX
        for running the bin/ directory files from a terminal rather than as an app
        invocation