disable hinting temporarily in config dialog and flipping mode and cropping dialog

Since hinting is of little use in these situations.

frontend/ui/reader/readercropping.lua

@@ -63,6 +63,8 @@ function ReaderCropping:onPageCrop(mode)
 	-- backup original page scroll
 	self.orig_page_scroll = self.view.page_scroll
 	self.view.page_scroll = false
+	-- backup and disable original hinting state 
+	self.ui:handleEvent(Event:new("DisableHinting"))
 	-- backup original reflow mode as cropping use non-reflow mode
 	self.orig_reflow_mode = self.document.configurable.text_wrap
 	if self.orig_reflow_mode == 1 then
@@ -110,6 +112,8 @@ function ReaderCropping:onCancelPageCrop()
 end
 
 function ReaderCropping:exitPageCrop(confirmed)
+	-- restore hinting state
+	self.ui:handleEvent(Event:new("RestoreHinting"))
 	-- restore page scroll
 	self.view.page_scroll = self.orig_page_scroll
 	-- restore view bgcolor