WP Smush Pro 3.16.8

Enhance: Minor UI/UX details

Enhance: Plugin UI/UX
Enhance: Compatibility with NextGen
Fix: CDN parsing of background images
Fix: Image counter when re-checking images
Fix: Bulk Smush counter going over total number of images
Fix: Bulk Smush counter on network admin

- New: Tutorials sections
- Enhance: Update the modal that displays the highlights of this release
- Enhance: Compatibility with NextGen
- Enhance: Compatibility with SVG images
- Fix: Image resize detection styles
- Fix: Tracking option on network subsites
- Fix: Lazy load placeholder background colors
- Fix: Lazy load custom placeholders on network installs
- Fix: Jetpack CDN compatibility
- Fix: Notice on CDN page