Added more article features

Added more article features.
Article date, comments and sidebar.

Also: The file images/captcha/.empty is there for git to create the directory
'images/captcha', which is required for the catcha system to work.

    application/views/article_date.php        (+)
    application/views/comments.php            (+)
    application/views/sidebars/sb_article.php (+)
    images/captcha/.empty                     (+)
Added RSS Feed Creator

Added RSS Feed Creator
    application/controllers/feed.php (+)
    application/views/feed.php       (+)
    application/views/header.php
Added Javascript Files

Added Javascript Files
JQuery, scrollspy, and some custom stuff.
    application/views/footer.php
    application/views/header.php
    javascripts/jquery-1.10.1.min.js (+)
    javascripts/scrollspy.js         (+)
Utility page for loading github gists

Allows loading files from external domain (gist.github.com)
For usage with asynchronus loading with JS.

    gist.php   (+)
Set SyntaxHighlighter to use custom CSS

Set SyntaxHighlighter to use custom CSS
    application/views/parser/code.php
Updated README to mention jQuery framework

Updated README to mention jQuery framework
    README.md
Refactored some javascript functions.

Refactored some javascript functions.
    application/views/footer.php
    javascripts/custom.js
Added common util functions for articles.

Added common util functions for articles.
    application/controllers/articles.php
    application/views/common_article_util.php   (+)
Added folder-info.txt files.

Added folder-info.txt files to ./analytics/ and ./images/captcha/

They explain the purpose of the folders, that would be otherwise empty on a
clone of the repository.

    analytics/folder-info.txt      (+)
    images/captcha/.empty          (-)
    images/captcha/folder-info.txt (+)
Improved code highlight header includes

Improved code highlight header includes
If no languages are specified, it doesn't add anything.
    application/views/parser/code.php
    application/views/parser/latex.php