* Remove spurious exports.
restify does not export the constructors for Server or
Router.
* Correct type of 'bunyan' export.
I'm not sure where the previous definitions came from, but
they definitely do not match restify 5.0.1.
restify.bunyan is not callable. It is a namespace that
contains various helper functions and objects relating to
logging with bunyan.
* Specify stricter types for ServerOptions.
`ca`, `certificate` and `key` are passed through to as
the corresponding options to https.createServer().
`spdy` is passed through to spdy.createServer().
* Correct type signature for formatters.
The `writeHead` method gets passed through to the native `response.writeHead`. The `Response` interface extends `http.ServerResponse` which defined the `writeHead` method with different arguments. For maintainability reasons, we should just use the inherited method. Also, the current definition makes this method useless (`writeHead` expects at lease one argument).
