The current scripting directory path given to Python on OSX is
`../data/obs-scripting`. This works when bin/ and data/ are in the same
folder like rundir after a compile and in the old .app bundles but the
new normal .app bundle structure is different.

For bundles move obspython.py and _obspython.so to the binary folder,
just like the Lua one, and pass that bin path to the Python interpreter
so it can find it.

The current working dir isn't guaranteed to be set with .app bundles
so look up binary path at runtime.

Add randr suport to the xshm plugin and prefer it over xinerama.

Add libxcb-xrandr0-dev as CI dependency

Without this, Fork and PR builds will fail.

Enable caption building by default on OSX to make captions usable
on OSX via scripting API.

As noted by ePirat, the VLC releases on GitHub are not official
releases, just repo snapshots. Use the official VLC 3.0.4 release
tarball to ensure maximum stability.

Fixes an issue where macOS builds on Travis would fail due to changes
in VLC master branch.

AppVeyor recently updated their Qt version to 5.11.2 which breaks
builds, because of the outdated path. Using this path should always
ensure that the newest subversion of Qt 5.11 gets used.

Closes obsproject/obs-studio#1482
Closes obsproject/obs-studio#1256

On Ubuntu 16.04 (Xenial), we have to build mbedTLS from source because
the version available from apt, mbedTLS 2.2.1, does not work with the
RTMPS implementation in OBS, which requires mbedTLS 2.7 at minimum. This
is due to the use of the function mbedtls_ssl_conf_dh_param_bin, which
was introduced in mbedTLS 2.7.

Build on Linux (Ubuntu 16.04) with AppVeyor. Disable PowerShell on
Linux. Ubuntu 16.04's dependencies are different from the existing
Ubuntu 14.04 dependencies, so a separate script for installing those
dependencies has been added.

Move the AppVeyor install scripts to a separate script file. This
shortens the appveyor.yml file and makes it easier to introduce new
install scripts for other build environments.

There is one minor change to the install script, and that was to change
directory back to the obs-studio git root directory.

(This also modifies the CI scripts accordingly)

It was difficult to build local obs-browser builds on macOS due to the
way the frameworks work and libraries are linked.  This solves that
issue so that local builds of obs-browser should always work fine.

This fixes a bug where the interact window would crash.

Pull Request #1420 changed the URL for the macOS deps package. When it
did that, it also changed the URL from HTTPS to HTTP. Since this asset
is available over HTTPS, we should use that.

* Add mbedTLS in brew install
* Update Sparkle from 1.16.0 to 1.20.0
* Update Opus from 1.1.3 to 1.2.1
* Update libogg from 1.3.2 to 1.3.3
* Update libvorbis from 1.3.5 to 1.3.6
* Update libvpx from 1.6.0 to 1.7.0
* Update Jansson from 2.9 to 2.11
* Update FFmpeg from 3.2.2 to 4.0.2