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   (+)
Minor fix to example layout

Minor fix to example layout
    application/views/articles/2014_08_whylinux.php
    application/views/jottings/2014_09_watermark.php
    images/entries/2014_08_whylinux/subtlemark.png       (+)
    images/entries/2014_08_whylinux/thumb-subtlemark.png (+)