refactored ws-lift-let into its own path.  passes units, testall_demos
refactored ws-lift-let into its own path.  passes units, testall_demos

rrnewton/WaveScript,rrnewton/WaveScript,rrnewton/WaveScript,rrnewton/WaveScript,rrnewton/WaveScript,rrnewton/WaveScript,rrnewton/WaveScript