Add supervisor-side LateShift views and controls.

Can be accessed under 'Reports'->'Late/Missed Shift Report'. Supervisors can view all late/missed shift and any employee-provided reasons for their lateness/absence. Supervisors may excuse or unexcuse late/missed shifts.

Signed-off-by: Max Fierke <max@maxfierke.com>
Remove ScrollToFixed reference from README.md

Signed-off-by: Max Fierke <max@maxfierke.com>