* Create `CorsOptions`
- `Cors` will be, in the future, an "optimised" or "compiled" version of
`CorsOptions`
- For now, `Cors` simply clones `CorsOptions` and `Deref`s to
`CorsOptions`.
* Update examples
* Remove usage of `Self` struct constructors
* Update Cargo.toml for Rocket `master`
* Prepare library for Rocket 0.4
TODO: check line 62 in `fairing.rs` to find better way than unwrapping
* Bump minimum nightly for Rocket 0.4
-removed conservative_impl_trait as it is no longer needed with the current compiler.
-removed allow(unmounted_route) as rocket no longer provides this linter.
* Bump Rocket, Rust version and remove impl trait flag
* Seems to build now
* Ignore Rocket documentation errors
* Update travis script
* Increase nightly version by a day
* Bump again