Erased the global loop thread
Erased the global loop thread

We can live off GLib's poll context system without an extra thread.
The Rust wrappers for refcounted objects will keep the context of
their creator thread's local context to achieve safe cross-thread use.

gi-rust/glib-sys,gi-rust/grust,gi-rust/grust-proof,gi-rust/gio-sys,gi-rust/gobject-sys