Fix travis config
Redirect page URLs to include slash prefix

- paths that don't end in either a file type (.html) are exported as
  directories with a index.html in them.

- a normal web server would redirect incoming URLs without an ending
  slash to the slash-ending variant

- now stasis does that too
Disallow paths that can't be served statically

- specifically paths with no file extension or ending in a slash
Release 2.0.0