Shortcode template edit page:
- make the template title more like page/post/shortcode title field
- fix for unsaved changes
Make sure template file exists
Custom shortcodes
- added help text for subcodes
- moved option and filter fetching into the shortcode classes
Make slideshow preview work properly
Shortcode preview window use button to popup the preview
Add description support to some form fields
Moved fetching shortcode options/filters into the shortcode class
Made sample template have unique classes to avoid clashes with placester themes
Regression bug fixes