Lat Long unexpected token, if negative

In my example I was able to reproduce the error if LAT/LONG had a negative value.

```
city.findPaths({
from: { lat: 51.672418464577476, -1.2798756107512863 }
})
```

Here is a screenshot of the unexpected token - https://i.ibb.co/mCGTKjR/Negative-LAT-LONG.png

I wonder if this is because of the position on the planet, or if I've done something wrong! [I hope it's not my stupidity!]

Start by running the city.findPaths example and inspect the API's handling of the from object and its latitude/longitude fields. Confirm the expected property names and verify that a negative coordinate is accepted without a syntax error; done means the example parses and the path lookup handles the negative value.

Written by the indexing model from the issue text.