message: Fix python3 string conversion
diff: @@ -77,7 +77,7 @@ cdef class hdlConvertor:
  filenames = [filename, ]
  if PY3:
  - filename = [item.encode('utf8') for item in filename]
  + filename = filename.encode('utf8')
  incdir = [item.encode('utf8') for item in incdir]
  return self.thisptr.verilog_pp(filename, incdir, mode)
  