Upgrade deps + small changes.

• Removed 12 bit per pixel option (not sure if this ever worked)
• Added default output path (out.png)

Bugfix

• Fixed image size calculations

Bitdepth Support

• Added --bitdepth=<bits> parameter with support for 1, 2, 4, 8, 12, and 24 bits-per-pixel.

1, 2, 4, and 8 bits-per-pixel corresponds to grayscale images.

Initial release

Basic functionality only:

• You can let binimage size the output image automatically (makes the image square)
• You can specify either the width or the height of the output image.