Write the BrowserID log to a file for later archiving.
Move BrowserID startup code out of Cucumber support.

It's much easier to redirect the BrowserID logs elsewhere in a shell.
(In fact, in JRuby, it's the only sane way: Process.spawn under JRuby
doesn't support stdout redirection.)
Archive BrowserID log output.

This might help me figure out what's up with these transient Travis
timeouts.
A better name for the default Selenium browser.