The recording popup window now closes when one of the options is chosen.
When recording is active, it is stopped automatically when the recording button is pressed. The popup remains visible while the button is being pressed, though it is hidden once the button is no longer being pressed.

Implements #247 symmetric supports

Closes #247

See merge request nicolas.pope/ftl!178

Implements #232 all source MLS

Closes #232

See merge request nicolas.pope/ftl!177

Implements #250 clipping operator

Closes #250

See merge request nicolas.pope/ftl!176

Resolves #251 rendering of point clouds

Closes #251

See merge request nicolas.pope/ftl!175

Fix FixstarsSGM CMake option

See merge request nicolas.pope/ftl!174

feature/vision mls

See merge request nicolas.pope/ftl!173

Add show bad colour option

See merge request nicolas.pope/ftl!172

Implements #244 360 environment background

Closes #244

See merge request nicolas.pope/ftl!171

Resolves #243 right eye transform bug

Closes #243

See merge request nicolas.pope/ftl!170

Resolves #242 no aa on right channel

Closes #242

See merge request nicolas.pope/ftl!169

Resolves #237 optimising MLS smoothing

Closes #237

See merge request nicolas.pope/ftl!167

Add source colouring option

See merge request nicolas.pope/ftl!168

The channel command line option is added to ftl2mkv. At most two
channels can be recorded from one stream. By default, the application
adds both channels to the mkv file as separate video tracks.

As the previous approach led to low performance, 2D video is now
captured to an ftl file, which removes the need to encode the video in
real time. The ftl file can be converted into a video file with ftl2mkv.

Implements #236 Fast Approximate Anti-Aliasing

Closes #236

See merge request nicolas.pope/ftl!166

Adds 2D video recording option to the GUI.

Implements #224 to use discontinuity mask

Closes #224

See merge request nicolas.pope/ftl!165

The GUI now has a snapshot feature. The record button opens a popup
window, which contains the different recording options.

The cog icon now opens a scrollable list of all of the registered
configurations, both local and remote. This window is created
dynamically each time the cog icon is clicked, so it now includes all of the
configurations that were available as the window was created.

Zoom and pan in GUI

See merge request nicolas.pope/ftl!164