Update front-edit.js

Editor should be destroyed before removing HTML element or in other case it'll throw Exception

```
TypeError: a is null
 at g<.proto.detach (/static/bower_components/ckeditor/ckeditor.js:931:281)
 at CKEDITOR.editor.prototype.editable (/static/bower_components/ckeditor/ckeditor.js:326:340)
 at .destroy (/static/bower_components/ckeditor/ckeditor.js:228:302)
 at front_edit_plugin.destroy_editor (/static/front/js/front-edit.ckeditor.js:29:9)
 at triggerEditor/< (/static/front/js/front-edit.js:95:13)
```
version 0.4.0, fixes Issue #6, thanks @syabro