Do a few micro-optimizations to reduce the number of memory allocations during thumbnail generation. This commit, combined with freezing string literals in a7dc05 and 67b961, reduces the number of allocations on the front page from 180,000 to 150,000, and the number of retained objects from 8,000 to 4,000.
Components
Components are used to encapsulate common UI widgets used throughout the site. This includes things like comments, tag lists, post thumbnails, paginators, and other things used repeatedly throughout the site. Components encapsulate a widget's HTML, CSS, and Javascript together so that all the code for a component is in a single place.
This uses the ViewComponent library.
Components are similar in concept to React components.