Major changes in Vanilla JavaScript Fullscreen Lightbox.

A large update for the vanilla JavaScript version.

The total size of the pro version of the plug-in was decreased from 64KB to about 50KB.
As for the basic basic version, from 34KB to about 29KB.

The new features:

• Added the "refreshFsLightbox" global function that detects new lightboxes and updates existing ones.
• Simplified the adding of the lightbox to a website, now it's only one JavaScript file.
• Through new functionality—custom sources—stuff such as Google Maps or iframes can be added.
• Changed the way of adding Vimeo videos, now you can do it through custom sources.
• You can now resolve the CORS issue through manually setting the source's type.
• Changed the way of listening to events.