merge attendance and leaveslip url confs
added related name for individualslip to event
added leaveslip display data (does not include leaveslip id)
small fix to ensure submit roll buttons work even if they are dynamically generated
fixed datetime.now() bug
new events property for GroupSlip, equivalent to IndividualSlip.events
changed excused to approved to match the model values
refactored. pass in individual and group leave slips in the same context variable, loop through all leave slips at once, attaching their information (id + status) to their respective events
resolved merge conflict in urls.py