Fasttracker II clone v1.89

• Fixed a possible crash on macOS (and possibly Linux) when loading a module whose filename includes special non-ASCII characters
• Added a "Default audio device" option when selecting input/output audio devices in the config screen. This option has a few edge-case bugs, though.
• Added an experimental Impulse Tracker module loader. This should only be used to extract patterns/instruments/samples, as there are severe conversion errors when this format is converted to XM under load. WARNING: This loader has not been thoroughly tested, and may cause a crash!
• Fixed a bug with the tracker scopes where the sample would sometimes not be displayed correctly during a sample/note trigger
• Replaced the Gaussian (SNES) interpolator with a 6-point cubic Hermite option. The Gaussian interpolator was very niche anyway, and as it sounded quite filtered, I think the vast majority of users wouldn't see a use for it.
• Added a few missing Norwegian/Danish alphabet letters to the main font (code page is now 850 instead of 437)
• Show extra digits (when space for them) in the C-4 Hz string in the instrument editor screen
• Again, slightly improved the interpolation method for the tracker scopes in "Lined" mode (when using the cubic/sinc interpolators)
• Slightly increased the contrast for the sample editor's loop pin lines