update build script so that running with npm start works

[KaneMorgan]

I think this addresses #19 but it may have been a different root cause looking at the dates

[Nyceane]

@KaneMorgan this still have the problem, not sure why you closed it

[KaneMorgan]

It didn't seem like this was still under active development. From what I can remember the bug is just that its looking at the wrong directory in the script, it should be looking at the doc rather than the web directory.

I started looking at this fork that someone else made https://github.com/DynamicEnvironmentSystems/pdf-annotate.js

I'm not actively looking at this anymore but it does fix an issue with getting started so I'll reopen it.

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