Remove agent modules, it is not yet implemented.

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
Add pagination.

 * Implemented Collection of Backbone.js and django REST framework.
 * The response json body of django REST framework is as folloing structure,
   but not compatible of default Collection of Backbone.js.
   {
     "count": <int>,
     "next": <url>,
     "previous": <url>,
     "results": [
       {
         "id": <id>,
         "attribute": <value>,
         ...
       },
       ...
     ]
   }
  * So I convert response at parse function at Backbone.Collection.extend.
  * The version of libraries:
    - django REST framework: 2.3.12
    - Backbone.js: 1.1.0

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>