Allows numberical strings as array index and make a call. e.g.,
callbacks['0']();

Added more test case for regexp (disabled by default, requires --call_regexp)
and call_as_function object created by API.

Review URL: http://codereview.chromium.org/1604

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@214 ce2b1a6d-e550-0410-aec6-3dcde31c8c00