Visual Design for Lessons

It seems like a lot of changes but it isn't -- it's because I branched on courses-design which has a lot of changes. Please code review that one (https://github.com/Eduki/eduki/pull/112) before reviewing this one. 

* Viewing and Creating Lessons have different designs
* Creating lessons redirects to lesson page of lesson that was just created
* Created tests for creating lessons
* Modified tests for viewing lessons

Files changed in this pull request are:

* app/assets/javascripts/models/lesson.js
* app/assets/javascripts/views/lessons/lessons_lesson.js
* app/assets/javascripts/views/lessons/lessons_new.js
* app/assets/templates/lessons/created.jst.ejs
* app/assets/templates/lessons/lesson.jst.ejs
* app/assets/templates/lessons/new.jst.ejs
* spec/javascripts/views/lesson_new_spec.js
* spec/javascripts/views/lesson_spec.js

@abboudm @DavidMah