Added delete method and activity to the One-one-ones.

Files Modified.

modified:   app/controllers/one_on_ones_controller.rb
modified:   app/helpers/students_helper.rb
modified:   app/models/one_on_one.rb
modified:   app/views/feed/show.html.haml
modified:   app/views/one_on_ones/index.html.haml
modified:   app/views/one_on_ones/show.html.haml
Added formatting to one-on-ones description. Now it respects the line breaks.
Added one_on_one url in the activity. Created relationships between Activity and OneOnOne. Created helper to render activities properly.

Files Modified.

modified:   app/controllers/one_on_ones_controller.rb
modified:   app/helpers/application_helper.rb
modified:   app/helpers/students_helper.rb
modified:   app/models/activity.rb
modified:   app/models/one_on_one.rb
modified:   app/models/student.rb
modified:   app/views/feed/show.html.haml
new file:   app/views/layouts/_alerts.html.haml
new file:   app/views/layouts/_navbar.html.haml
modified:   app/views/layouts/application.html.haml
modified:   app/views/one_on_ones/index.html.haml
modified:   app/views/one_on_ones/show.html.haml
modified:   app/views/students/show.html.haml