Consider migrating to Rocket.rs

[codesections]

As @sphinxc0re mentioned in #4, we could consider migrating the codebase to SergioBenitez/Rocket. This would have several advantages:

• Popular Rust web framework
• Potentially more familiar syntax for developers familiar with other languages/frameworks
• On path to running on stable Rust
• Uses latest libraries (e.g., futures 0.3.x)
• Will use async/await once they land

It would also have several cons:

• Not yet running on stable Rust
• Slower (at least last time I looked into the mater)
• No built-in support for Server Sent Events (but see Support for Server Sent Events · Issue #33 · SergioBenitez/Rocket)
• Less functional code (this is a personal preference, but I just really like the way Rocket handles its code flow—the idea of using filters is very functional and strikes me as very clean)
• Requires refactoring/rewriting existing code.

Overall, I have a strong preference for staying on stable Rust for an app that will run in production. So I currently plan to stick with Warp. But I'm certainly open to changing my mind if anyone convincingly argues in favor of Rocket (or a different framework). I'm also open to revisiting the issue if/when Rocket lands on stable Rust.