imv (image viewer for X and/or Wayland)

imv is a command line image viewer intended for use with tiling window
managers. Features:

* Native Wayland and X11 support
* Support for dozens of image formats including:
  * PNG
  * JPEG
  * Animated GIFs (requires FreeImage or libnsgif)
  * SVG
  * TIFF
  * Various RAW formats (requires FreeImage)
  * Photoshop PSD files (requires FreeImage)
  * WEBP
  * HEIF/AVIF (requires libheif)
* Configurable key bindings and behaviour
* Highly scriptable with IPC via imv-msg

Optional dependencies (autodetected):

- FreeImage (support for GIF, RAW, PSD formats)
- libnsgif (support for GIF)
- libheif (support for HEIF/AVIF)

If you don't have at least one of FreeImage or libnsgif, imv won't
support GIF images at all.
