disable word OCR for now

Since it will crash the reader with a strange error message saying
"terminate called after throwing an instance of 'DJVU::GException'"
even though only PDF file is opened.

frontend/ui/reader/readerdictionary.lua

@@ -12,7 +12,7 @@ end
 
 function ReaderDictionary:onLookupWord(word)
 	DEBUG("lookup word:", word)
-	if self.lipc_handle then
+	if self.lipc_handle and word then
 		-- start indicator depends on pillow being enabled
 		self.lipc_handle:set_string_property(
 			"com.lab126.booklet.kpvbooklet.dict", "lookup", word)

frontend/ui/reader/readerhighlight.lua

@@ -81,7 +81,7 @@ function ReaderHighlight:onHold(arg, ges)
 					word_box.y = word_box.y - math.floor(word_box.h * 0.02)
 					word_box.w = word_box.w + math.floor(word_box.h * 0.04)
 					word_box.h = word_box.h + math.floor(word_box.h * 0.04)
-					local word = self.ui.document:getOCRWord(self.pos.page, word_box)
+					-- local word = self.ui.document:getOCRWord(self.pos.page, word_box)
 					DEBUG("OCRed word:", word)
 					self.ui:handleEvent(Event:new("LookupWord", word))
 				end)