change the way 4K resolution is determined.

Older versions of
tvheadend incorrectly report 1080i channels as having 1088 vertical
pixels so they got classified as 4K. The algorithm is now changed
to consider source as 4K only when the total pixel count exceeds
6 megapixels.
dvdplayer: use startpts as a time reference if no other is available

This avoids display of wrong time after seek, due to lack of timestamps
dvdplayer: remove code that set limit on smallest frame rate

This skips the "slow" motion video after seek, by instead starting
playback when next frame is to be displayed
dvdplayer: always output the first frame after seek/startup without wait

This make sure we get something new on display after seek, even if
the next frame is to be displayed sometime later
dvdplayer: avoid busy waiting for video renderers to get a buffer
coreae: when a flush is requested delay is zero

On seek, the flush was requested, but not performed when delay
was requested, leading to stuttering on seek.
allow remote access to "special://skin" directory
allow remote access to "special://profile/addon_data" directory
Merge pull request #4065 from Montellese/remote_access_paths

Allow remote access to special://skin and special://profile/addon_data
Merge pull request #3680 from Jalle19/fix-4k-detection

fix false 4K detection on some 1080i and 3D sources
Merge pull request #4051 from elupus/seekframe

Seekframe