This was caused by the custom image capture pipeline. I've switched back to
using camerabin's image capture. I don't particularly like having to use a temp
file, but it will work for now.

Also, fix a bug in the tests.

Fixes #12.

The function's logic was incorrect and only worked on images with 4 channels.

Fixed the branch/commit for gst-plugins-bad.

Also, fix a refcounting bug that came up during testing.

- Documentation updates
- Refcounting

Instead of using device manager indexes to represent cameras, use the new
ApertureCamera objects.

ApertureCamera objects represent a camera connected to the system. They can be
obtained using an ApertureDeviceManager. This makes for a cleaner API, because
operations on a specific camera can be done with an ApertureCamera object
rather than on the device manager using an index.

It also paves the way for device-specific code using ApertureDevice. This is a
class that is meant to be subclassed for different devices, such as the
PinePhone or Librem 5, that Aperture might be used on. These implementations
will provide features such as camera flash and support for trickier camera
switching cases. The implementation is chosen at runtime based on things like
device tree name.

ApertureDevice is a private API. It is considered an implementation detail and
is not meant to be stable. ApertureCamera is mostly public, and applications
can use it to get information about the camera and do things like turn on/off
the flash. It also has some internal methods for working with GSt...

This fixes 0eaa2f71

It has not been needed for quite some time.

This is a way to query basic software/device information to paste in bug
reports.

viewfinder: Remove duplicate line

This way, distributions that do not intend to make their Aperture package
depend on ZBar and its GStreamer plugin (although they should) do not have to
patch Aperture in order for the tests to pass.

In environments where ZBar should be a dependency and its absence would be an
issue, the `barcode_tests_skippable` option in Meson should be set to `false`.

The callback was never initialized, which sometimes caused errors.

- Make aperture_viewfinder_take_picture() and
aperture_viewfinder_stop_recording() async functions. This replaces the old
method, which was to emit signals when the operation was finished.

- aperture_viewfinder_take_picture() no longer saves the image to a file. It
only returns a pixbuf, and it is up to the application to save it.

- Redo error handling. The async functions now return errors when they fail,
instead of putting the viewfinder in the error state or doing nothing.

- Taking pictures is now done with a gdkpixbufsink rather than the image-capture
signal on the camerabin. This is simpler because it gives the viewfinder more
control over the process.

Fixes #7.

When a branch was removed, often a GStreamer pipeline error would occur because
the operation was not completed in the right order (due to concurrency in
GStreamer).

Solved by adding a pad probe, which schedules an async call, which changes the
state and removes the branch from the pipeline. This ensures everything is
done in the right order.

This test uses the dummy device provider to create a camera feed with a QR
code, then make sure the code is detected by the viewfinder.

Previously, if there were no cameras plugged in and you plug one in, the
viewfinder would not notice. It would remain in the NO_CAMERAS state and you
wouldn't be able to use it again.

The new on_camera_added() handler checks whether the viewfinder is in the
NO_CAMERAS state, and if so, sets the viewfinder to use the new camera.

Generate test coverage reports and upload them as artifacts in CI.

Device manager tests are run using a dummy device provider in GStreamer. This
way, they can run in a predictable manner and work even on machines that do
not have cameras attached. This will also be important later when specific
camera feeds are needed, such as in barcode detection testing.

Also, organized the tests directory. Each section of the tests gets its own
file, and main.c is used for registering and running all of those tests.

Added a utils.c file for various test utility functions.

Add aperture-enums.h to the sources of the declare_dependency target, to make
sure it is built before the demo/tests.

A commit has been added to the 1.16 branch, which broke the flatpak build and
CI.

GIR annotations were missing from aperture_init. The annotations indicate that
the argument is an array and is a reference (in/out) parameter.

This allows the function to be used properly in Vala.

Build Vala language bindings, and make both that and GObject Introspection
generation optional.

aperture_barcode_type_from_string() was missing in aperture-utils.h

Apparently a comment that says "NOCOMMIT" doesn't work unless you actually
check for it before committing...

aperture_pipeline_tee_add_branch() takes our reference to the ZBar element,
so we should not try to free it. We do still need to set it to NULL to
indicate that it is no longer valid.

Kind of important.

It's only tangentially related to taking pictures and videos, and it's much
simpler for Aperture's code to just put the gtksink code in ApertureViewfinder's
init function.

Fixes #10.

- Fix indentation for meson.build files
- Remove Vala rules, since the project no longer has any Vala code
- Add rules for more file types

Build documentation using gtk-doc.

Moved a few things around to make the docs better. Private headers now have
their own directory. Added a couple missing SECTION: comments. Fixed
any other documentation problems that were causing gtk-doc warnings.

Docs are published to GitLab Pages using CI.

Fixes #9.

g_list_store_find() was introduced in GLib 2.64, which hasn't landed in some of
the build images that will be used for CI. This commit introduces a temporary
replacement for that function.