Add rotate right option (#1268)

README.md

@@ -292,6 +292,7 @@ OUTPUT SETTINGS:
                         Split output into multiple files. 0: Don't split 1: Automatic mode 2: Consider every subdirectory as separate volume [Default=0]
   --spreadshift         Shift first page to opposite side in landscape for two page spread alignment
   --norotate            Do not rotate double page spreads in spread splitter option.
+  --rotateright         Rotate double page spreads in opposite direction.
   --rotatefirst         Put rotated spread first in spread splitter option.
   --filefusion          Combines all input files into a single file.
   --eraserainbow       Erase rainbow effect on color eink screen by attenuating interfering frequencies