This commit introduces TLS support, provided by `rustls` and a fork of
`hyper-rustls`. TLS support is enabled via the `tls` feature and
activated when the `tls` configuration parameter is set. A new
`hello_tls` example illustrates its usage.
This commit also introduces more robust and complete configuration
settings via environment variables. In particular, quoted string,
array, and table (dictionaries) based configuration parameters can now
be set via environment variables.
Resolves#28.
* All From* trait methods are now named like the trait.
* All From* traits have an associated Error type.
* Document all of the `form` module.
* Add codegen tests for auto-derived forms.
* The param parsing traits now live under Request.
* Add content-type responsers for JSON, HTML, and plain text.
* Use content-type responders in content_type example.
* Conditionally create Request `from` HypRequest.
* Clean-up dispatching and handling in main rocket.
* Change Level enum to Logging Level and reexport.
* Allow users to set logging level before launch.
* Fix content_type example error handling.
* Percent decode params when user requests `String`.
Sergio Benitez