Investigate gio's GResource to get rid of make_images.rb

[ben0x539]

https://developer.gnome.org/gio/stable/gio-GResource.html

https://developer.gnome.org/gio/stable/glib-compile-resources.html

Possible complications are probably that thing not being widely-enough available, non non-recent or non-linux systems, but glib-compile-resources seems to do the same thing as make_images.rb.

[ben0x539]

There's also a thing that'd store images as C literals in the right format to create a GdkSurface from immediately. We should probably get rid of the cairo stuff eventually anyway.