trillium-testing-v0.4.1

This release changes all calls to block_on when reading request or response bodies to futures_lite::future::block_on, allowing it to be called within a tokio runtime. Although this would be undesirable for async performance in a production system, it's find for single-task testing.

Additionally, TestConn::run_async is now public, allowing for testing within an async test harness such as #[tokio::test] or #[async_std::test].