Initial somewhat stable release (Mac only).

This early release includes:

• Basic selection/sequencing mechanics.
• Extremely basic file export capability.
• Somewhat working "Open with..." menu.
• Support for all popular formats, including TIFF and RAW (via libraw). TIFF support needs some love with regards to color management - sometimes the colors are off.
• There's a number of known bugs, but things mostly work.

Note: the build is an Intel Mac one, but is confirmed to work on M1 through Rosetta 2.