v0.9.0-pre19

BINDINGS/C++: Added comment on C4251
BINDINGS/C++: Use unique_ptr
COMMON: Added more BPP16 RGB[X] pixel formats
COMMON: Added sail_io_contents_to_data() and sail_io_contents_into_data()
COMMON: Make sail_now() return 0 on error, not SAIL_OK
EXAMPLES: Fixed using bytes per line (ignored previously)
ICO: Added ICO image format
LIBSAIL: Make codec priorities as enum
PCX: Added PCX image format
QOI: Added QOI image format (https://phoboslab.org/log/2021/11/qoi-fast-lossless-image-compression)
SAIL: Install licenses of third-party components (standalone bundle only)
SAIL: Move icons to every codec directory
SAIL: Run ldconfig in Travis only on Linux
SAIL: Run sail --version on Travis to make sure the binary is functional (no missing dependencies etc.)
SAIL: Update benchmarks