Log Message:
Import gtkwave-3.3.53 as wip/gtkwave.

GTKWave is a waveform viewer which supports waveform data in
the following formats:

(vcd) VCD/EVCD -- Verilog Value Change Description files
(out) Synopsys Timemill/Powermill/Nanosim .out files
(lxt) Tony Bybell's LXT format, which can be generated by Icarus Verilog