add last_percent field in pdf/djvu document history

And normalize last_percent for cre document

frontend/ui/reader/readerpaging.lua

@@ -77,6 +77,7 @@ end
 
 function ReaderPaging:onCloseDocument()
 	self.ui.doc_settings:saveSetting("last_page", self.current_page)
+	self.ui.doc_settings:saveSetting("last_percent", self.current_page/self.number_of_pages)
 end
 
 function ReaderPaging:onTapForward()

frontend/ui/reader/readerrolling.lua

@@ -104,7 +104,7 @@ end
 function ReaderRolling:onCloseDocument()
 	local cur_xp = self.ui.document:getXPointer()
 	self.ui.doc_settings:saveSetting("last_percent", 
-		10000 * self.ui.document:getPosFromXPointer(cur_xp) / self.doc_height)
+		self.ui.document:getPosFromXPointer(cur_xp) / self.doc_height)
 end
 
 function ReaderRolling:onTapForward()
@@ -214,7 +214,7 @@ function ReaderRolling:gotoXPointer(xpointer)
 end
 
 function ReaderRolling:gotoPercent(new_percent)
-	self:gotoPos(new_percent * self.doc_height / 10000)
+	self:gotoPos(new_percent * self.doc_height)
 end