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.
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
videolibrary: add choice to resume video when using "Play using..." (fixes #14358)
videodb: only re-draw progress bar when progress has changed in CleanDatabase()
platinum: lastPlaybackTime is in the "upnp" and not in the "dc" namespace
Merge pull request #4073 from Montellese/videodb_clean_speedup

videodb: speed up CleanDatabase()
Merge pull request #4063 from Montellese/play_using_resume

videolibrary: add choice to resume video when using "Play using..." (fixes #14358)
VideoInfoScanner::GetFanart: fix: don't dereference null pointer
VideoThumbLoader::LoadItemLookup: don't try to load any art for "add" button
Merge pull request #4075 from Karlson2k/fix_add_cover

fix: FileItem::FindLocalArt: don't try to find fanart for "add" button
[info] don't ToLower() info conditions prior to resolving them - we need only compare them caseless in the info store
Merge pull request #4082 from jmarshallnz/case_sensitive_infobool

[info] don't ToLower() info conditions prior to resolving them
fixed: use the proper make instead of calling 'make' directly

fixes builds on freebsd
cmake buildsystem