Update mocha to 1.20.1.
http resolver test: Also allow an ESOCKETTIMEDOUT error when expecting an ETIMEDOUT.

The test fails on travis because it gets ESSOCKETTIMEDOUT, but it doesn't really make a difference.
http resolver: Test that the retrying logic handles timeouts after the headers have been received.
Update cssom-papandreou to 0.2.4-patch6.

https://github.com/papandreou/CSSOM/pull/2