Import exercises: allow for entries without matrikel number
                  group field changed to 'not required'
Merge branch 'master' of github.com:cwyss/student-manager
Print exam list: checkbox list and exam title in header
Merge pull request #13 from rbreu/master

Template tag for static data; total_points sortable
Merge branch 'master' of github.com:cwyss/student-manager
static data key 'lecture' for headings
exam mark and final mark added
master exam mark_limits: validation added
listeners added to update marks
enter exam reults: total points editable
print exam list: result lists added
print exam list: handle 'did not attend' case
print exam list: output of mark intervals added
Query exam data added
query exam: select examnr and generate point groups
Import exams: ModelChoiceField for exam number in form
TODO.txt; exam: filter by resit
print exam results full: column 'subject' added
static/print.css: larger .points width
Merge branch 'master' of github.com:cwyss/student-manager