Rework core/complex parts of code to be testable in Node

[msiebuhr]

We're beginning to have some quite complex code in the client. Quite a lot of it doesn't touch the DOM, so we should be able to unit-test it before we build/deploy changes.

Stuff I'd like tested:

• Core search engine (http-pub/js/search.js)
• Bits in http-pub/js/app.js: isCharCode(), Bram's unicode-surrogate/BMP-stuff, data parsing/loading/indexing, location.hash-handling, etc.

I imagine splitting the code into separate modules that works both in browsers and Node.js, and then do the testing there.