Split out glib and cairo

[acertain]

glib and cairo are useful (and used) on their own, and it would be really nice to have access to high-level bindings for them without depending on gtk+

[GuillaumeGomez]

@jeremyletang and me were talking about that. We agreed on creating an organization when rgtk will be in a more advanced stage of development. Then, we'll split every libraries to allow users to use only one. Unfortunately, that's not our priority for now. It still remains a lot of work on rgtk.

But thanks for your interest. Feel free to contribute on this project !

[gkoz]

It might be preferable to do the split earlier rather than later (this doesn't mean splitting the repo) so that any refactorings would be constrained by the crates structure from the beginning (think coherence rules for example). If we accidentally rely on everything being in one crate, it could be very difficult to split later.

[GuillaumeGomez]

It will be in a very near future. @jeremyletang and I will have more time at the end of the month. I thought a PR proposed to split each lib in its own directory. I have to check.

[alexlarsson]

A bit offtopic, but how does the glib part of rgtk compare to: https://github.com/gi-rust

[gkoz]

@alexlarsson
I believe glib here has mostly been focused on the needs of the GTK bindings. Some parts of it may have bitrotten. I'm playing with some ideas for making it less true to the GIR letter and more Rust-y.