Add a manga reading mode which displays image in reverse order in double page mode.

The mode is triggered by selecting the "21" double page icon next to the double page icon.

YACReader/render.h

@@ -126,6 +126,7 @@ public slots:
 	QPixmap * getCurrentPage();
 	void goTo(int index);
 	void doublePageSwitch();
+	void doubleMangaPageSwitch();
 	void setRotation(int degrees);
 	void setComic(Comic * c);
 	void prepareAvailablePage(int page);
@@ -182,6 +183,7 @@ signals:
 private:
 	Comic * comic;
 	bool doublePage;
+	bool doubleMangaPage;
 	int previousIndex;
 	int currentIndex;
 	//QPixmap * currentPage;