Error on first load of non-index path when spa is true

[robinchew]

Run liven with spa: true, go to localhost:3000/non-index-path, errors with the following:

(node:23462) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'reverses' of undefined
    at P (/home/robin/work/livereload/node_modules/@alumna/liven/dist/liven.cjs.js:1:14448)
    at G (/home/robin/work/livereload/node_modules/@alumna/liven/dist/liven.cjs.js:1:16984)
    at Server.<anonymous> (/home/robin/work/livereload/node_modules/@alumna/liven/dist/liven.cjs.js:1:51256)
    at Server.emit (events.js:198:13)
    at parserOnIncoming (_http_server.js:695:12)
    at HTTPParser.parserOnHeadersComplete (_http_common.js:111:17)
(node:23462) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
(node:23462) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Node version 10.32.2 lts dubnium.