Allows the ability to see whether an audio source listed in advanced
audio properties is currently active or inactive (i.e. in an inactive
scene)

Allows the ability to modify the properties of inactive audio sources
which may in scenes other than the one that is currently active.

Allows the ability to save replays with a button rather than with the
keyboard if desired.

Closes obsproject/obs-studio#1954

When we use the server error to respond to user's failing to start a
stream it is slow to return an error and unclear to the user what went
wrong. This diff introduces a simple settings check before attempting
to stream and catch and explain specific URL/key issues to the user.

In the case of preset services we check there is a Stream Key before
attempting to start a stream.

In the case of "custom" we only verify there is a URL since for some
services that's all that is required or the user may use user/password
authentication.

Adds an option to the right click menu in the scenes widget to switch
modes. When in regular list mode, it'll let you select grid mode, and in
grid mode, it'll let you select list mode. Grid mode changes the scenes
widget to have a grid of buttons for scenes rather than a list, much
like XSplit.

Both BTTV and FFZ are fairly popular however they do occasionally
interfere.  To give users the option to chose whichever one they like
most we add a new setting that allows BTTV, FFZ, both, or neither.

Defaults to "None" for new users.  Existing users will be migrated to
"Both" as that's the previous behavior.

Most of the top streaming services now have a link in the stream key
label. Upgrading this button to a button clarifies the assistance
for the important step of setting up a stream.

Creates a new type of button for URL opening simply which also
automatically updates the tootip to the current URL.

Includes addition of Twitter/Periscope URL to make this feature more
complete.

This reverts commit b5843caa.

This breaks some hotkeys because the signals are tied to a signal which
is now triggered because "toggled" is used instead of "clicked", so just
revert it for now for the release and look at it later post-patch.

This commit fixes various issues with screen readers in the main OBS
interface. These were tested using NVDA on Windows 10 1903.

Checkboxes or buttons which toggle, when receiving an activate signal
from the screen reader would visually update, but not perform any
action. This is because they're listening only for clicks. They should
all now be listening for toggles instead.

The screen reader would navigate through the UI in the order that
elements are defined in the .ui XML, and not by their row positions.
The XML has been reordered so that things should be defined in their row
order.

Audio track selection now says Track 1, 2, etc, rather than just the
number. Various checkboxes that just say "Enable" now have accessible
text that says what the enable is for (since it says "checkbox", the
fact it's an enable should hopefully be clear). Type in the recording
tab of output now has accessible text which says "Recording Type".

All the right side buttons in hotkeys now have tooltips, and by
extension, accessible text. Currently it does not yet say what hotkey
the action is in relation to, but that would require more locales.

Adds dynamic bitrate support (marked as beta) to the advanced settings
for now.

Downscale will either fetch 2x2, 2x3, 3x2, or 3x3 texels.

Now that Lanczos downscale blurring has been removed, the Area shader
can attempt to fill the void.

Allows the ability for users to add custom browser widget docks that
they can use for their third party services if they feel the need,
mostly as a convenience tool so they don't have to open extra browsers
alongside the program.

OBS has an option to warn before stopping a stream, but it doesn't have
a similar warning for recording. This can result in a recording being
unintentionally stopped.

Add an option to warn when the "Stop Recording" button is pressed.

Note: While OBS also has an option to warn on stream start, this
patch purposefully does not add similar warn on recording start option.
This is because accidentally starting to record isn't risky in the same
way that accidentally starting to stream is.

Adds support for pausing recordings.  When settings are eligible for
recordings, a pause button will appear next to the recording button.  If
the settings are not eligible, it will warn the user in the output
settings that they cannot pause recordings if those settings are used.

Twitch will now return a 403 HTTP error code if you attempt to query
your stream key when your Twitch account does not have two-factor
authentication enabled.  This handles it a bit better and displays an
appropriate error message for users so they know where to go to enable
it.

(This commit also modifies the UI, obs-ffmpeg, and obs-output modules)

Fixes a long-time regression where the program would lock up if an
encode call fails.  Shuts down all outputs associated with the failing
encoder and displays an error message to the user.

Ideally, it would be best if a more detailed error could be displayed to
the user about the nature of the error, though the primary problem is
the encoder errors are typically not something the user would be able to
understand.  The current message is a bit of a generic error message;
improvement is welcome.

Another suggestion is to try to have the encoder restart seamlessly,
though it would take a significant amount of work to be able to make it
do something like that properly, and it sort of assumes that encoder
failures are sporadic, which may not necessarily be the case with some
hardware encoders on some systems.  It may be better just to use another
encoder in that case.  For now, seamless restart is ruled out.

This commit adds a preview to the properties window for transitions.

The preview will play back the transition at the global transition
duration or the transitions fixed duration, between two private scenes
with an A and B label, and different background colors.

libobs: Add support for limited to full color range conversions when
using RGB or Y800 formats, and move RGB converison for Y800 formats to
the GPU.

decklink: Stop hiding color space/range properties for RGB formats, and
remove "YUV" from "YUV Color Space" and "YUV Color Range".

win-dshow: Remove "YUV" from "YUV Color Space" and "YUV Color Range".

UI: Remove "YUV" from "YUV Color Space" and "YUV Color Range".