Changed controllers and helper methods and views relating to home controller.

logged_in? helper method
root is now home controller
sessions new is now a partial
  *session will now be created when student signs up
  *student will be directed to list of his/her courses
  *option to create a new course is hidden if student
    is logged in.
  *when teacher signs up he/she will have a proper session
  *when teacher signs up will be directed to courses list
  *when teacher is on course list page he/she can make
    a new course
Merge pull request #8 from bootcoder/home_login_logic

Changed controllers and helper methods and views relating to home contro...
resolving merge conflicts
Merge pull request #9 from bootcoder/courses_index_spike

Courses index spike
fixed merge conflicts
resolved issues with sessions