sort the dropdown list of categories alphabetically when editing a post

Publish a post with future date or time, it will go into scheduled posts.

Allow to use tag like C++ and double check for the same tag slug.

See: https://jqueryui.com/autocomplete/#multiple

system/htmly.php
- Loads language files from folder lang/
- Sets language settings for date and time format
system/includes/dispatch.php
- function i18n() returns translated strings

Without the step modifier users on Chrome mobile couldn't edit
blogs because the seconds were missing
(hh:mm while hh:mm:ss was expected)

This is my first commit, hope it worked :)

Simplify add and edit content. Bugs fixes and improvements.

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

Add category feature to the core.

Fix the date and time on the edit content page so it will displayed as
year, month, day, hour, minute, and second.

Trying to add content type: image, video, audio, link, and quote. No
styling yet.

Add post draft feature for the blog post.

Update the jquery to 2.1.4 and cleaning up the image upload codes.

Adding image upload to the markdown editor using
jQuery.AjaxFileUpload.js.

Styling, performance tweak, and bugs fixes.

FI & Video

Added remove_html_comments function

User role support

Various improvements

Change admin panel.