Provide debug event listener with access to the debuggee context. Also introduce new event listener setter that allows to set a callback that accepts single parameter encapsulating all debug event details so that additional information can later be passed to the listener without breaking compatibility with existing clients.

Review URL: http://codereview.chromium.org/2108024

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4693 ce2b1a6d-e550-0410-aec6-3dcde31c8c00