deps/media-playback: Simplify seek/time code

CI: Fail osx and linux on build failures. Fix decklink clang-format

UI: Add missing function delcaration

This broke the build, but due to an issue with CI this was not caught by
CI.

decklink: Log decklink API version on plugin load

UI: Add Chromium-compatible NSApplication subclass

This fixes some crashes in browser panels on Mac, but it's also harmless
if browser panels aren't enabled.

libobs: fix obs_sceneitem_group_XXX_item API

`obs_sceneitem_group_add_item` and `obs_Sceneitem_group_remove_item`
were leaving the affected scene in an inconsistent state.

To resolve, simplify and make the code more readable, we replace the
manual linked lists mutation with existing `detach_sceneitem` and
`attach_sceneitem` calls.

libobs: Fix Mac linker error

Adds API:
obs_scene_add_group2
obs_scene_insert_group2
obs_sceneitem_group_ungroup2

These functions should be used by plugins if they need to use these
functions and need to send a refresh signal.  If a major API rework ever
happens the old functions should be removed.  The old functions should
eventually be deprecated.

The reason why specifying a 'signal' parameter is useful is because it's
a bit more seamless for the user interface to be able to have custom
handling of these specific cases.  It looks better and doesn't require
completely erasing/recreating the entire list, which is visually
unappealing.

Fixes a bug where the UI would not know that a group had been updated.

This signal is used to specify when a scene needs a full refresh of its
item list.

Non-static inline functions don't work for some reason.

docs/sphinx: add media controls and source icon

Fix OpenGL thread-safety on Mac to use latest Xcode

README.rst: Remove retired CI services

UI: Use absolute path for portable mode multi-instance check

UI: Show source icons in Advanced Audio Properties

Travis and AppVeyor have been retired in favor of Azure Pipelines.

Also re-order Crowdin and Discord badges and fix indentation of Azure image.

UI: Fix transitions being disabled

win-capture: Faster display / window capture updates

UI: Always prompt when updates are available

obs-ffmpeg, vlc-video: Add media control support

Co-authored-by: NVodBox <dillon@vodbox.io>