Adding checks to the alerts for student training.

Fix for ORA-728 and ORA-729 - Alert messages when there are no training examples and alerts when student training is disabled.

Now checking both scenarios before display an alert. Added tests accordingly. 

@wedaly @gradyward 
You can use query chaining to make this more succinct:
```
$(criterionOption).val("')
    .addClass("..")
    .click(..)
```