This reverts commit 8a22889e.

After further usage, result is undesirable.  We don't need the theme
applied to projectors.

libobs: linux-v412: obs-ffmpeg: Add packed BGR3 video support

libobs: Remove unnecessary frame pipelining

libobs: Improve low-resolution bilinear sampling

libobs: Disable blending when converting sources

This fixes the issue where limited-range RGB sources were being
composited with dirty render targets.

Fixes a bug where if the user gave a custom color to a source list item,
the edit box used with renaming the item would also have that
background color while editing the name, awkwardly.

If the user gave the source list item a custom color, the "background"
stylesheet value would apply to children of the item widget, causing the
lock/eye checkboxes to also have that background color added on top of
the chosen color.  This is fixed by explicitly settings the background
value to none on the lock/eye checkboxes.

Apparently certain versions of Qt have a bug where the tray icon's
internal "visible" variable is set to false despite the fact that it
still shows.  Calling show() first before calling hide() sets the
internal boolean value and fixes the issue with the hide call.

UI/updater: Various updates

UI: Fix output icon size. Add padding to settings list items

UI: Fix transition A/B labels on macOS/Linux

Previously, if the video size in OBS was too big, the labels would not
render on macOS/Linux due to the labels not fitting inside the texture
in the freetype plugin. This change makes it so that there is a maximum
size for the label, rather than being solely based on video size.

This change also makes the labels look centered on macOS/Linux, as
unlike the GDI plugin on Windows, the freetype plugin aligns the bottom
of the text with the bottom of the source.

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.

Allows the ability to use things such as links in warning dialogs,
optionally.  Disabled by default.

This can take a while on a hard drive since it hashes the entire OBS
installation, show a undetermined progress marquee to avoid users
thinking that the updater has frozen.

Someone mentioned this format preserves the most quality for a
particular capture card using V4L2.

CI: Build CEF with OS X 10.11 target

CI: Fix travis test on OSX

UI: Revert Dark theme Scenes font change

This fixes a pixelated font on high-DPI

Remove three instances of unnecessary double-buffering. They are not
needed to avoid stalls, and cause increased memory traffic when
measured on Intel HD 530, presumably because texture data will remain
in cache if sampled immediately after write.

(Note: GPU timings from Intel GPA are volatile.)

NV12, 3 Draws:
RGBA -> UYVX: 628 us -> 543 us
UYVX -> Y: 522 us -> 507 us
UYVX -> UV: 315 us -> 187 us
Total, Duration: 1594 us -> 1153 us
Total, GTI Read Throughput: 25.2 MB -> 15.9 MB

win-wasapi: Speaker enum fixes

Remove KSAUDIO_SPEAKER_2POINT1 because it is included in the Windows
SDK. (I'm guessing it wasn't before.)

Redefine 4POINT1 as KSAUDIO_SPEAKER_SURROUND|SPEAKER_LOW_FREQUENCY
instead of KSAUDIO_SPEAKER_QUAD|SPEAKER_LOW_FREQUENCY. See definitions:

FFmpeg 4.1: FL+FR+FC+LFE+BC
WASAPI QUAD: FL+FR+BL+BR (looks wrong)
WASAPI SURROUND: FL+FR+FC+BC
WASAPI LOW_FREQUENCY: LFE

Fixes "Toggle Preview" hotkeys from duplicating when profiles are
switched.  The hotkeys were not being unregistered.