improve transitions for hovercat drop-down menu at desktop width (bug 1096654)
Added recommendation opt-out (bug 1072637)
fix `window.performance.now` polyfill (bug 1090572)
Merge pull request #787 from cvan/fix-performance-polyfill

fix `window.performance.now` polyfill (bug 1090572)
Merge pull request #784 from cvan/nav-hovercat-transitions

improve transitions for hovercat drop-down menu at desktop width (bug 1096654)
[wip] replace isotope (100KB) with salvattore (5KB) for feed layout (bug 1092331)