Forum spoiler

The extension adds a spoiler on ajax to the forum
Functions and capabilities:
- nesting spoilers into each other, with the ability to limit the nesting level (only for 3.1)
- loading images in the spoiler only after opening the spoiler
- reducing the size of images added to the message with the tag img
- filtering images from unwanted domains
- redefinition of image addresses or substitution of a thumbnail for an image (manual addition in the file)
- hiding images added via the img tag
- hiding images added through the img tag that are in user signatures
- choosing a way to open images processed by a spoiler, 1 - in a new window, 2 - in the current window, 3 - using prettyPhoto/Highslide/Lightbox2/Fancybox3 (with a choice of a theme)
- display all images on one page in gallery mode
- the use of some bb codes in the spoiler header (only for 3.1)