DVDCodecs: Amlogic: Handle conditions in which amcodec should be opened during Open()

DVDCodecs: Amlogic: Use mpeg2 video codec for mpeg2's

* AM Video Codec cannot properly handle the still-frames within DVDs

Signed-off-by: Brandon McAnsh <brandonm@matricom.net>

DVDFactoryCodec: Remove throttling of mpeg2 to libmpeg2 for amlogic

* Thanks to @kszaq, am-mpeg2 can handle all mpeg2's however it can't handle the still frames (which is caught above it).
* Testing .VOB isn't setting hint.stills to true so will need to address this in separate patch

Signed-off-by: Brandon McAnsh <brandonm@matricom.net>

DVDFactoryCodec: Further conditionalize HAS_LIBAMCODEC opening

Signed-off-by: Brandon McAnsh <brandonm@matricom.net>

DVDFactoryCodec: Amlogic: Force rmvb to ffmpeg

Signed-off-by: Brandon McAnsh <brandonm@matricom.net>

DVD: Amcodec: Handle conditions in which amcodec should be using during open

* Instead of before

Signed-off-by: Brandon McAnsh <brandonm@matricom.net>
[musicdb] fix incorrect use of ComputeCRC, causing playcounts to not update. Thanks to amet
Merge pull request #4590 from tamland/nav-sound-fix

Fix: navigation sounds from user config directory are never loaded
Merge pull request #4598 from jmarshallnz/plugins_run_as_plugins

[plugins] ensure we lookup the add-on as a plugin before trying any other extension point
Merge pull request #4576 from koying/fixamcart

FIX: [mediacodec] ART is not happy with non-existent values in map
Merge pull request #4587 from fritsch/xbmc-upstream

AlarmClock: Show correct string for shutdown timer
Merge pull request #4589 from FernetMenta/aefixes

ActiveAE: fix idling of engine due to high number of samples in sink buf...
Merge pull request #4593 from FernetMenta/dxva

dxva-hd: fix past/future frames and a/v sync
Merge pull request #4581 from FernetMenta/epg

pvr: fix duplicate EPG IDs if EPG is not stored in database
Merge pull request #4583 from fritsch/xbmc-upstream

ffmpeg: Backport c94305ae23318c8956a30485cd5642829f4f16a9 to fix #15085
Merge pull request #4580 from jmarshallnz/anim_length_fix

[guilib] animation length was calculated incorrectly from effects
Merge pull request #4579 from jmarshallnz/display_path_to_delete

when deleting files, make sure we display the path
Merge pull request #4572 from arnova/rar_subs

fixed: Downloading subs for rars was broken
Merge pull request #4591 from amet/subs_fixes

Subs search fixes
Merge pull request #4575 from koying/fixdroidcolor

FIX: [droid] missing color in labels
[musicdb] joins against album and song artist views should be LEFT, as some songs/albums have no artist. fixes #15149
[gui] don't show the 'remote path not found' message on directory failure unless it's a share. closes #15091, #15133.
[osx] fix make build on osx
[tests] fix CharsetConverter.utf8To_UTF32LE test on osx
[tests] fix HttpHeader test