wxString in Nyquist prompt makes trip to UTF8 and back properly...

... Simple test:  In Nyquist prompt enter

(progn "Ü")

Using Alt+U, U.

Formerly it came back mis-encoded.

src/effects/nyquist/Nyquist.cpp

@@ -1861,7 +1861,7 @@ bool NyquistEffect::ParseProgram(wxInputStream & stream)
       return false;
    }
 
-   wxTextInputStream pgm(stream);
+   wxTextInputStream pgm(stream, wxT(" \t"), wxConvUTF8);
 
    mCmd = wxT("");
    mIsSal = false;