Fixes for running on Linux

Hi Ryan,

This pull request supersedes the one I just sent you. Sorry, we thought we'd do them as separate pull requests, but we didn't have separate branches.

The first commit uses the gem (phantomjs) that can find Phantom on the path. Note that it says it will try to download and install it (at runtime!) if it can't find it on the path. We never ran this code path so cannot speak for it :)

Second commit uses console.log in the JS test runner. Using 'fs' to write to /dev/stdout was giving unpredictable behavior. Console.log seems to work everywhere (mac & linux).

Let us know if you have any questions.

Mike and Phil