Middleware for serving static resources.

This installs a static() method in the application that accepts the following arguments:

• `base`: the base resource directory (required)
• `index`: the name of a file to serve if the path matches a directory (e.g. "index.html")
• `baseURI`: a common prefix for a resource URI (e.g. "/static")
• `options`: an object with fine-grained configuration options
• • `servePrecompressed`: if true (default), static resources with a pre-compressed gzip equivalent will be served instead of the original file.
  • `maxAge`: set the `Cache-Control` header in seconds, default is 0.
  • `lastModified`: if true (default), set the `Last-Modified` header to the modification date of the resource.
  • `setHeaders`: allows a user to specify a function which returns additional headers to be set for a given path. The given function produces an object containing the header names as keys and takes the path as argument. User-provided headers take precedence over all other headers.
  • `dotfiles`: determines how should files starting with a dot character be treated. `allow` (default) serves dotfiles, `deny` respond with status 403, `ignore` respond with status 404.

You can call static() multiple times to register multiple resources to be served.