more frequent refresh, show loading spinner after we appear
(so that we’re the selected view controller already)
each ArgusProgramme now sends a notification when it starts/finishes

EPG Grid uses these to update view per cell immediately
the EPG autoUpdateTimer now has to do less, so can be called more often

can use these in What’s On and Programme List too next

also some dead code removal
fixing whitespace/indentation
move StartTime/StopTime optimisation into ArgusProgramme to keep it hidden
EPG Grid micro-optimsations