update css from source

We were having some issues with the icons appearing on the toolbar. For example instead of the BulletedList icon, the numberedlist_icon is being displayed. I noticed that vendor/assets/javascripts/ckeditor/skins/moono/editor.css in the gem is different from the one on http://ckeditor.com/apps/ckeditor/4.3.1/skins/moono/editor.css.

eg. looking at the css rule for the class '.cke_ltr.cke_hidpi .cke_button__bulletedlist_icon', on the gem the css rule is "{background: url(icons_hidpi.png) no-repeat 0 -1320px !important;background-size: 16px !important;}" but from the source its different ".cke_ltr.cke_hidpi .cke_button__bulletedlist_icon{background:url(icons_hidpi.png) no-repeat 0 -1296px!important;background-size:16px!important}"...
after updating the file, the icons are displayed correctly.