[rbp/omxplayer] Reset display region when video stream properties change

Currently when video stream properties change, e.g. when user switches to next or previous Live TV channel, and has the same frame width and height, the COMXVideo::SetVideoRect() method is not called, causing the video to play back with default source and destination rectangles, not respecting the user-defined zoom settings.

This commit fixes the issue.
settings: a setting should be disabled if its parent setting is disabled
[videodb] don't set the playcount to previously matched episode/season when adding new episodes if the new episode doesn't have a defined episode and season number. fixes #15234
Merge pull request #4666 from codesnake/reset_display_region_when_stream_properties_changed_in_omxplayer

[rbp/omxplayer] Reset display region when video stream properties change
[info] Only extract thumbnails and video info from real video stream
[Pydocs] Add info for Player and RenderCapture

1) Added information in comments to be pulled into PyDocs describing the
shortcomings when calling xbmc.player.getPlayingFile() for LiveTV.
Specifically that pvr:// url's are not translated into usable filenames
or streams.
2) Added information to xbmc.CapturePlayer regarding the functions
getHeight() and getWidth() which return 0 prior to calling
CapturePlayer.capture(). Also added that getAspectRatio() may be called
prior to issuing a capture() request.
Merge pull request #4771 from Montellese/settings_disabled

settings: a setting should be disabled if its parent setting is disabled
Merge pull request #4779 from popcornmix/real_thumbnail

[info] Only extract thumbnails and video info from real video stream
Merge pull request #4789 from KenV99/master

[Pydocs] Add info for Player and RenderCapture
Merge pull request #4775 from jmarshallnz/empty_episode_playcount

[videodb] don't set the playcount on scan if missing episode/season numbers
FIX: [AE] if null sink is requested, return null sink