* Mark DocumentManager's old events as deprecated *before* extensions have
a chance to register for them. Clean up docs.
* Fix $() shim warning: it was incorrectly flagging r.js-concatenated
extensions as core code, since the whole path prefix is wiped off in that
case. Unfortunately the same is true of core code in production builds,
making the two indistinguishable. So: only flag as core code when the path
indicates a dev build