Allow for CKFinder skin customization.

[Jakub Ś]

Currently when user wants to add new custom skin to CKFinder not only he has to create skin.js and CSS files but also add some code in ckfinder.js file - a.skins.add('myskin', (function () {... })());.
The same thing happens when user copies one of default skins folder, renames it and makes appropriate changes. Such new skin will not be visible for CKFinder if user doesn’t add this skin to the minimized ckfinder.js.

Would be nice if this code from ckfinder.js could be moved to skin.js and the only change user should do, would be change in config.js file.

This issue was reported by user Kevinelsh on our support channel – “Support question: Customizing CKFinder Skin”.