tracking/list: Rename GND to AGL

As AGL means above ground level whereas GND stands for ground
flights/view: tighter zoom to flight
flight.js: Pass placeholder to initPhasesTable() function
Merge branch 'master' into flight-collection

Conflicts:
	skylines/templates/flights/map.jinja
	skylines/templates/flights/view.jinja
	skylines/templates/tracking/map.jinja
	skylines/templates/tracking/view.jinja