Version 0.3.0

Features:

• Use the improved OpenGL image view widget from MazeAmaze/Syntalos
• lib: Add callbacks to retrieve the current raw and displayed frames
• Use C++17 as baseline
• Add AppStream MetaInfo file
• Simplify & improve time keeping code
• lib: Permit API users to intercept & modify timestamps

Bugfixes:

• Lower required OpenGL version, and fail if we can't initialize GL
• Never even try to use dark mode on systems where it doesn't exist
• Perform sanity check on timestamps before initializing timer with them
• Do not expose clock details in API
• Don't resend settings when framerate is low, this only causes the problem to get worse
• Prefer V4L as camera API on Linux
• Prefer DirectShow as camera API on Windows
• Improve locking code and handle dropped init frames better