show my courses as list

Fix #315

Changes in this PR:

1. order courses by their creation date, latest course will move to front
2. If a user has more than 3 courses, we will display them as a list

Things to discuss:

1. Should we always display them as list (even they have less than 3 courses) ? 
2. Do we need to hide the table header or even remove the creation time field ? 

UI Preview:
![screen shot 2014-12-17 at 5 52 40 pm](https://cloud.githubusercontent.com/assets/4983239/5469477/165bf83a-8617-11e4-821d-788e10b9c4ae.png)