added a few buttons for discipline_list.html
fixed a few functions in attendance/util.py and term.models.py
changed reportview.html to discipline_report.html
added AttendanceAssign view that shows disicplines to be assigned to trainees
changed all the buttons into a better looking one
able to assign life study according to attendance in current period
added a selection in attendance_assign.html to select the period to look at
able to assign Discipline according to attendance.Roll