Update esrefactor to revision 34bc6e461e (Apr 21 2013).

https://code.google.com/p/esprima/issues/detail?id=420
Implement the rename refactoring demo.

https://code.google.com/p/esprima/issues/detail?id=420
Update esrefactor to revision c5081d5385 (Apr 23 2013).

https://code.google.com/p/esprima/issues/detail?id=420
Merge branch 'master' into gh-pages