Bug fixes

Fixed bug in the getFilters and getImages

Fixes
- Twitter link

Changes
- Better docs

- Overdue updates
- Drupal 9 compatibility

New: Multi-step form support
Fix: JS params
Fix: AJAX forms handler
Other minor improvements

Mark as compatible with Drupal 9
Ajaxed content doesn't make it to the page
Deprecated function drupal_render_root()
Allow more control over modal-header and modal-body
Remove bootstrap lib