Refactor: Article/Jotting merge, w/more

Refactor: Article/Jotting merge, w/more

Jottings and articles are now handled by the same controller and model.
These are collectively called "entries".
The sidebars have also been merged.
RSS feed has been fixed. Correct ordering can be improved.

    application/config/routes.php
    application/controllers/article.php       (-)
    application/controllers/errors.php
    application/controllers/feed.php
    application/controllers/jotting.php       (-)
    application/controllers/pages.php
    application/models/article_model.php      (-)
    application/models/entry_model.php        (+)
    application/models/jotting_model.php      (-)
    application/views/articles/2013_06_cpp_setup.php
    application/views/articles/2013_08_oeis.php
    application/views/articles/2013_11_skittles.php
    application/views/articles/2014_08_whylinux.php
    application/views/common_article_util.php
    application/views/feed.php
    application/views/jottings/2013_10_gamedev01.php
    application/views/jottings/2014_01_nicekill.php
    application/views/jottings/2014_01_screenrecord.php
    application/views/jottings/2014_02_watchfile.php
    application/views/jottings/2014_04_screenrecordalt.php
    application/views/jottings/2014_05_lcov.php
    application/views/pages/entries.php       (+)
    application/views/sidebars/sb_article.php -> application/views/sidebar.php
    application/views/sidebars/sb_jotting.php (-)