include working versions of js libs in the repo

[gambhiro]

It would be helpful if you included working versions of the different js libs in this repo. While they are usually reliable, I've just downloaded the latest junr.js, and had to fix some trivial issue in it.

[slashdotdash]

@gambhiro I've added Bower to manage the client side dependencies for this Jekyll plugin. You now have two options that should simplify usage.

1. Run bower install and then rake build to pull down 3rd party JS libs and build the plugin
2. Simply copy the pre-built Ruby plugin and JavaScript minified JS file, with all dependencies included, from the build directory: https://github.com/slashdotdash/jekyll-lunr-js-search/tree/master/build