Concern show page modifications for DLTP-173

 * Create 2 column layout for Abstract.
 * Put representative_image into a span3 column and rest of content into
   span9 column.
 * Reduce some vertical space that seemed excessive between h2 heading
   on page.
 * Add word-break to external links urls that are way too long and set a
   minimum width for external links actions.

dltp-173#
Merge pull request #38 from ndlib/dltp-173

Concern show page modifications for DLTP-173