Show message if placeholder course in student home page is still inconsistent during user interaction #1637

For Issue #1637 

Added a message to evaluation submission if course is detected to be affected by eventual consistency: 
"Updating of the course data on our servers is currently in progress and will be completed in a few minutes. Please wait a few minutes to submit the evaluation again."

Another message was added to viewing evaluations:
"Updating of the course data on our servers is currently in progress and will be completed in a few minutes. Please wait few minutes to view the evaluation again."

Example of how the message looks on staging server:
![ss](https://cloud.githubusercontent.com/assets/6832286/3157632/c236b1f6-eaf7-11e3-9169-8e24ebc35218.png)