Fixes and improvements

• Breaking change: Use dyn keyword to avoid deprecation warning (#223)
• Breaking change: Update url dependency to v2 (#234)
• Breaking change: (async) Fix Script::invoke_async return type error (#233)
• Add GETRANGE and SETRANGE commands (#202)
• Fix SINTERSTORE wrapper name, it's now correctly sinterstore (#225)
• Allow running SharedConnection with any other runtime (#229)
• Reformatted as Edition 2018 code (#235)

BREAKING CHANGES

Use dyn keyword to avoid deprecation warning (#223)

Rust nightly deprecated bare trait objects. This PR adds the dyn keyword to all trait objects in order to get rid of the warning. This bumps the minimal supported Rust version to Rust 1.27.

Update url dependency to v2 (#234)

We updated the url dependency to v2. We do expose this on our public API on the redis::parse_redis_url function. If you depend on that, make sure to also upgrade your direct dependency.

(async) Fix Script::invoke_async return type error (#233)

Previously, invoking a script with a complex return type would cause the following error:

Response was of incompatible type: "Not a bulk response" (response was string data('"4b98bef92b171357ddc437b395c7c1a5145ca2bd"'))

This was because the Future returned when loading the script into the database returns the hash of the script, and thus the return type of String would not match the intended return type.

This commit adds an enum to account for the different Future return types.