Allow choice between STDERR and STDOUT

[hickey]

I have a situation where Atlassian Bamboo is being used for deployments (Don't blame me--not my choice). Unfortunately, in log() of node.js the file descriptor is hard coded to stderr. This causes everything to come out blood red in the logs. Not exactly the best thing to see in logs.

With Bamboo the way to prevent this is to write the logs to stdout and then the output would be treated as normal log output and not display in red.

Unfortunately, my knowledge level of NodeJS is not that great, but I think I just found how this could be triggered. Expect to see a PR in a few mins.