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Fixes #26 

I went ahead and added jQuery, Underscore, and LESS, even though we don't really need them yet; I figure we will eventually. 

At the moment, we're just building the LESS on the client side, but presumably there's something for building it on the server side that we can do at some point. 

Note that I've also moved the openseadragon client-side files into the public/lib folder. 
What do you think about doing this on the server (or at build/deploy time) instead of adding another client library?