Fixed sidebar button style

Fixed sidebar button style
    application/views/sidebar.php
    css/style.css
Made bootstrap buttons swarminglogic colors

Changed the bootstrap-themes to have button colors matching the theme
used otherwise on swarminglogic.com

    css/bootstrap-theme.min.css
Improved example images

Improved example images
    application/views/jottings/2014_09_watermark.php
    images/entries/2014_09_watermark/keyfunc-input.png
    images/entries/2014_09_watermark/keyfunc-output-extended.png
    images/entries/2014_09_watermark/keyfunc-output-overlay.png
    images/entries/2014_09_watermark/subtlemark-example.png
    images/entries/2014_09_watermark/thumb-keyfunc-input.png
    images/entries/2014_09_watermark/thumb-keyfunc-output-extended.png (-)
    images/entries/2014_09_watermark/thumb-keyfunc-output-overlay.png  (-)
Added 'subtlemark' to examples in  2014_08_whylinux

Added 'subtlemark' to examples in  2014_08_whylinux
    application/views/articles/2014_08_whylinux.php
    images/entries/2014_08_whylinux/subtlemark-wm.png   (+)