Improve printing images to console

[Athari]

More modes of displaying images:

1. full background character (current);
2. half-height box chartacters;
3. shade box characters;
4. RGB/256 colors if OS/terminal supports it (see Support operating system-specific features like more colors and font style #14).

More image sources:

1. WPF/WIC (current);
2. WinForms/GDI+;
3. ImageSharp;
4. *nix native something?

Also make image sources pluggable instead of current weird internal dependencies.

See also Display a Image in a console application.