This major release of Surf contains substantial improvements through a variety of changes and additions.

(Note: this is a cumulative list of changes since Surf 1.0.3)

Notable mentions include:
- Uses stable standard library `futures`!
- Much more type compatibility with Tide via http-types!
- Re-usable `Client` which is able to make use of connection pooling under the hood.
- Reduced generics for `Client` and `Middleware`.
- Re-worked `Middleware` to use `async_trait`.