Disable spellchecking in notes until it can be supported for real

https://forums.zotero.org/discussion/19771/workaround-to-disable-spell-checker/

Right now you can't iteract with it (to add/ignore words) or change the
language (which is probably only English in Standalone) or disable it
(without going to about:config).

resource/tinymce/note.html

@@ -14,7 +14,7 @@
 		button_tile_map : true,
 		language : "en", // TODO: localize
 		entities : "160,nbsp",
-		gecko_spellcheck : true,
+		gecko_spellcheck : false,
 		convert_urls : false,
 		
 		handle_event_callback : function (event) {