Add expandable control to display additional lines of the description

 * Added the readmore.min.js jQuery UI plugin. This lets us show/hide
   the text when javascript is available without having to add any
   special markup when preparing the content.
 * Change the truncation length on description/abstract fields to 350
   from 150
 * Add additional js and css to support the above changes.

dltp-231#
Merge pull request #48 from ndlib/dltp-231

Add expandable control to display additional lines of the description