Update to CKEditor 4.4.5 with codesnippet plugin

As discussed yesterday on IRC.  

**NOTE:**  I did notice that the browser cache needed flushing on *one* Bolt instance before the button's icon image showed up.

**EDIT:** Is it worth adding http://docs.ckeditor.com/#!/guide/dev_codesnippet to config.yml.dist to point people at the required template additions, or best to assume a dev is a dev?