Reverted change to crossfilter.min.js after a filtering bug was discovered

Clicking 'DE' followed by 'ES' on the language chart caused the genre bars to disappear.
This bug doesn't occur when using the full crossfilter source.
Using crossfilter 1.3.7 minified.
Fixed reference to crossfilter.1-3-7.min.js
Merge pull request #180 from niksoper/gh-pages-dev

Reverted crossfilter.min.js to version 1.3.7