Fully support PHP 8.x

Glob() is expensive so cache the category files.

Make the footnote link absolute when on teaser

The ported version of Twenty Fifteen and Twenty Sixteen include with the
package. Maintenance and bugs fixes.

Prepare quick release since even though only small changes but its
important. See commit #2fca100

Improving template engine for more flexible theming. Add
cache.expiration.

Prepare release, improvements, and bugs fix  #226

Updated robots.txt + new htaccess files.

I made the following changes for the robots.txt and .htaccess files.

# robots.txt updated
- Allow theme assets (CSS, JS, Images, Fonts) for SEO
- Allow folder with uploaded images (/content/images)

# .httaccess files added
- /content - Deny all
- /content/images - Allow only jpg|png|gif
- /cache - Deny all
- /system - Deny all
- /system/admin/editor - Allow all
- /system/resources - Allow all
- /themes - Deny all
- /themes/blog/css - Allow all
- /themes/blog/fonts - Allow all
- /themes/blog/images - Allow all
- /themes/blog/js - Allow all
- /themes/clean/css - Allow all
- /themes/default/css  - Allow all
- /themes\default\img - Allow all
- /themes\logs\css - Allow all

Ready for release. Include post draft feature.