Create whole kaboodle for Marking guide

1. Create a forum
   1. Set the whole forum grading to Point
   2. Set the advanced grading to Marking guide
2. Create a marking guide with:
   1. several criterion
   2. several FUCs
3. Create some content as a couple of different users
4. Login as teacher
5. Press the "Grade" button
   1. Confirm that you are shown all of the criterion in the grading panel
6. Play...
   1. Use some of the FUCs
      1. Confirm that they are appended to the existing comments that you have
   2. View the description of each criterion
   3. Enter values
7. Switch to the next user
8. Switch back again
   1. Confirm that the values you entered before remain

Note: Invalid value detection is not yet finished. This is a problem with the grading panel itself, and not with the specific implementation. Invalid values will cause the whole thing to be lost right now. It's on the TODO list.