Fixes #14

• We needed to upgrade fontawesome in order to have a grip icon for the find box. I removed the built-in css file and used the node module instead. A couple of icons now have different names, which have been updated.
• I added JQueryUI in order to make use of the drag functionality (for the search box).
• pull-left used to be a bootstrap class that used float: left, but they dropped it a long time ago. The only reason pull-left still works is because it is a class used in fontawesome, which they have now also removed. Anyhow, bootstrap calls it float-left in the bootstrap version in this build, so it is renamed in multiple files.
• The bulk of the new filter functionality is in browse.js and search.js.
• The resize listener that moved the nav panel has been moved to views/layout.twig where it belongs.
• The new css class table-striped-rookie replaces table-striped. This css class is improved and preserves zebra striping in tables where some rows are hidden.