Make the footnote link absolute when on teaser

Added theme copyright for Twenty Fifteen & Twenty Sixteen.

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

Support Chinese, Japanese, Arabic etc. for the slug (post url, tag and
category).

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

Simplify add and edit content. Bugs fixes and improvements.

Use URLify, add pager number, new variable etc.

Add active menu link to custom menu

Prepare release, improvements, and bugs fix  #226

Add new config: static.frontpage = "true" to enable the static
frontpage.

Use the pagedown extra instead of standard pagedown. Adding
sitemap.category.xml

Add category feature to the core.

Updated robots.txt  + added new htaccess files. by @greenphp

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

404 pages rendered within layout by @greenphp