PGS subtitles: Update RemoveOldSegments to account for unknown end time.

This was broken after d8deeda49e270d02e9eae795265494184f409b29, some subtitles could be wrongly removed.
Initialize members and remove unused ones.

Fixes CID #1192565
Fix: MoveVideoWindow() might not be called when needed after 7c6a1ce
("Don't MoveVideoWindow() during fullscreen toggle")

We need to call MoveVideoWindow() to properly handle EC_VIDEO_SIZE_CHANGED event.

Refs #4178
Cosmetics for MoveVideoWindow() method.
DVB: Don't update stats when channel is not active.
DVB: Show current event time in the status bar.
DVB: Make use out of the DVBState struct.
Mpeg2SectionData: Minor refactioring of the ParseEIT() method.
DVB: Cosmetic for SetChannel().
Cosmetics for timers.
Cosmetics for stats.
DVB: Fix time calculations.

StartTime could have been inaccurate in certain cases.
DVB: Add channel name to snapshot filename.
DVB: Add only supported services.
DVB: Add context menu to the navigation dialog.

Use std::vector to store channel in order to get better sort abilities.
DVB: Use proper media types.

Resolves ugly audio pops and cracks for EAC3.