Added the logic (service + routing + controller) for the course exercises and their categories.
Added the service for the course exercises and their categories.
Added the routes for the course exercises and their categories.
Updated the exercise category's ID value.
Added the controllers for the exercises and their categories.
Removed unimplemented routes.
Added partial layouts (stubs) for exercises and their categories.
Added the exercises' categories titles in the collective data file.
Finished the logic for the exercises routing, controllers and service.
Merge origin/gh-pages into gh-pages

Conflicts:
	app/js/app.js
	app/js/controllers.js
	app/js/services.js
Added questions content to the detailed-data files.
Completed the logic of the questions controller.
Adjusted the data structures, for the exercises' questions.
Adjusted the views, for the exercises' questions.
Added the presentation inclusion note.
Added the exercises block.
Fixed a problem within the pagination layout.
Performed spelling check.
Release of version 2: added the exercises section.