Start the Sauce Connector. Returns childProcess object.
function startConnector(username, apiKey, exitCb) {
    var jarPath = process.env.SAUCE_JAR || path.join(__dirname, "thirdparty", "Sauce-Connect.jar")
    var jcmd = "java"
    var jargs = ["-Xmx64m", "-jar", jarPath, username, apiKey]
    var screencmd = "java -Xmx64m -jar " + jarPath + " [USERNAME] [API KEY]"
    
    ctx.comment("Starting Sauce Connector")
    var opts = {
      cwd: ctx.workingDir,
      cmd: {
        command: jcmd,
        args: jargs,
        screen: screencmd
      }
    }
    connectorProc = ctx.cmd(opts, exitCb)
    // Wait until connector outputs "You may start your tests"
    // before returning
    connectorProc.stdout.on('data', function(data) {
      console.log(">>", data);
      if (/Connected! You may start your tests./.exec(data) !== null) {
          console.log(">> STRIDER-SAUCE :: TUNNEL READY")
          return cb(null, true)
      }
    })
  }