Monitoring cache with Claspin

Introduced Claspin, a monitoring tool that uses heat maps to visualize the health status of Facebook's cache systems (Memcache and TAO). Claspin encodes tribal knowledge about metric 'badness' into a visual format, allowing engineers to quickly assess cache health at a glance. It processes server-side stats and renders heatmaps in the browser using SVG, with real-time updates. Enhancements include support for additional backends, custom palettes, and revision-controlled configuration files.