Library infrastructure for MediaWiki/Initial project pitch

This is a project under consideration by the WMF MediaWiki Core team for late 2014. See Wikimedia MediaWiki Core Team/Quarterly review, October 2014 and Wikimedia MediaWiki Core Team/Backlog

Currently, MediaWiki encourages monolithic design by virtue of making tightly-coupled code the easiest way to incorporate new functionality into core. This project would accomplish the following:
 * Incorporate the infrastructure for splitting out libraries for third party use
 * Port some widely used functionality to this infrastructure with a goal of making new libraries only need to depend on the widely used functionality (now in library form) rather than the whole of MediaWiki

Candidates for this work
 * MediaWiki components
 * CLDR parser
 * cssmin
 * HashRing
 * Aaron's UUID generator
 * Zip directory reader
 * PHP JSON parser
 * Monolog
 * Profiler
 * There is a lot of code that is reusable save for wfDebug / WfProfile calls are often the only things
 * CSSJanus
 * ResourceLoader
 * Other components
 * Pybal

Benefits:
 * Encourages developers to think in terms of clearly-defined interfaces
 * Makes pluggable implementations (services) easier
 * Make our developers more efficient by organizing the code into simple components that can be easily understood.
 * Being open and inviting to the outside world
 * Share our awesome libraries with others and encourages contributions from them even if they aren't particularly interested in making our sites better.