Release 1.0

[wmanley]

TODO:

• Can we get the gv! macro to return a type rather than a value?
  • No, according to @rodrimati1992 on reddit: https://www.reddit.com/r/rust/comments/gup2al/crate_review_request_gvariant/fskbhyq/ . So instead:
• Add define_gv! macro to define named GVariant types, or maybe replace the gv! macro entirely and require GVariant types to be named.
• Are my uses of unsafe safe? Could they be avoided?
• Is it reasonable to have RefCell in the public API? Would it be better to remove it?
• Is it important to implement types (and validation of) object path and type signature types?
• Would there be any value in splitting aligned_bytes or casting into their own crates? Or can I replace parts with an existing popular crate?
• Set up CI
• Fix cargo test attempting to compile my doc comments
• Fix CI to run all the relevant tests, fmt and clippy.
• Is this suitable to be recommended to be used instead of the GLib implementation in the glib-rs documentation? If not why not and can this be improved accordingly?