Feature: support embedded images in terminals through proprietary escape codes

[marcastel]

Provide -- possibly through a custom configuration or CLI option, support for terminals (such as iTerm2) that support inlined images. For instance:

![](myimage.png)

would be translated to the following proprietary escape sequence:

ESC ] 1337 ; File = [arguments] : base-64 encoded file contents ^G

And the image would be displayed inline (width should probably be auto-adjusted to terminal's column width).

Rather than hardcoding such proprietary sequences, these could be documented in the configuration file, and, if present, used to embed the image).