Fixed syntaxhighlighter <pre> usage bugs

Fixed syntaxhighlighter <pre> usage bugs by moving to <script> with <[CDATA[]]>
    javascripts/custom.js
Made shStart(), shEnd() to mark syntax-highlights

Made shStart(), shEnd() to mark syntax-highlights blocks.
Syntax highlighter content is now within <script> instead of <pre> blocks.
This fixes the issue with '<' and '>', amongst many other things.

Also fixed various other minor issues.

    articles/2013_06_cpp_setup.php
    articles/2013_08_oeis.php
    articles/2013_10_gamedev01.php
    articles/2013_11_skittles.php
    articles/2014_08_whylinux.php
    common_article_util.php
    jottings/2014_01_screenrecord.php
    jottings/2014_04_screenrecordalt.php
    jottings/2014_05_lcov.php
    jottings/2014_09_watermark.php