LearningObjectCategory model changes. No south yet.
Merge branch 'master' into LearningObjectCategory
migrations for LearningObjectCategory model and category field in LearningObject model
safety commit
Changed to semantics of the order of the exercises in the course module. The table is ordered by the order of the exercises and the categories don't have orders anymore. Also implemented the rendering of the categories to the template. Also restricted categories of same course_instance to not being able to have same name. The South migration will be in the next commit.
Removed order from admin and updated the migrations.
Numbers back to the course module table.
Made the buttons also respect the order field of LearningObject instead of loop counter.
Merge commit '1dc60ec337c21b9baeee4c98cab8611412c3654d' into LearningObjectCategory
Schemamigration merge
Removed done TODO comment
Added categoy field to the BaseExerciseForm so the exercise creation in teacher's view doesn't break. However, the teacher's view doesn't fully support categories yet. In addition to this, users with Django superuser and Django staff status may now access the teacher's view and the exercise creation view.
Merge pull request #59 from Rubinous/LearningObjectCategory

Learning object category
In previous commit, the get calls for the QuerySet objects self.students and self.exercises caused QuerySet evaluation on every loop iteration in the __collect_student_grades method. This was not the intended behaviour. Now the data of those QuerySets should be loaded in to memory all at once so there are not too much database query overhead. Note that the memory usage might get high.

Also filtered out submissions in self.best_submissions that were not bound to any submitters anymore.
Merge commit '86f0725f14c54486dee7aba9c9f0dbbdabd39dbd' into results_view_improvement
Changed the wird looking submitters__gt=0 to exclude clause with submitters=None
typo fix
Merge pull request #61 from Rubinous/results_view_improvement

Fixed results view to be faster (in cost of memory) and deal with orphan submissions (submissions without submitter)