Issue 1670 - Removed "Hide placeholders" option from the UI (Firefox)

chrome/content/ui/fennecSettings.xul

 <?xml version="1.0"?>
 
 <!--
   - This file is part of Adblock Plus <http://adblockplus.org/>,
   - Copyright (C) 2006-2014 Eyeo GmbH
   -
   - Adblock Plus is free software: you can redistribute it and/or modify
   - it under the terms of the GNU General Public License version 3 as
   - published by the Free Software Foundation.
   -
@@ skipping 13 matching lines @@
 %filtersDTD;
 ]>
 
 <vbox xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
   <setting pref="extensions.adblockplus.enabled" type="bool" inverted="true" title="&disable.label;"/>
   <setting type="control" title="&subscriptions.tab.label;">
     <menulist id="adblockplus-subscription-list"/>
   </setting>
   <setting id="adblockplus-acceptableAds" type="bool" title="&acceptableAds2.label;"
     oncommand="/**See bug 762015*/ if (event.type == 'oncommand') {event = document.createEvent('Events'); event.initEvent('command', false, false); this.dispatchEvent(event);}"/>
-  <setting pref="extensions.adblockplus.fastcollapse" type="bool" title="&hideplaceholders.label;"
-           inverted="true"/>
   <setting id="adblockplus-sync" type="bool" title="&sync.label;"
     oncommand="/**See bug 762015*/ if (event.type == 'oncommand') {event = document.createEvent('Events'); event.initEvent('command', false, false); this.dispatchEvent(event);}"/>
 </vbox>