Recommendation to relatively reference neo4j-javascript-driver

[gregoryfoster]

I was able to get legis-graph-spatial up and running locally, but ran into one simple issue which the project may want to address.

At index.html:12, we use an absolute reference to pull in the browser-version of the neo4j-javascript-driver. For initial testing, I'm using a file:// reference to pull up a local version, and since that's not installed at my filesystem root, the absolute reference fails. If we change that to a relative reference, I don't think there should be any side-effects on the functioning of the project regardless of whether it's installed in a subdirectory.

<script src="lib/neo4j-web.min.js"></script>