Document how to setup a SauceLabs account and configure for testing

Running grunt does the build. But grunt test fails at the intern:functional task. It seems that it fails when opening the tunnel to SauceLabs due to missing credentials.
The grunt test output is:

Running "intern:functional" (intern) task
Verifying property intern.functional exists in config...OK
File: [no files]
Options: runType="runner", config="tests/intern.js", functionalSuites=["tests/functional/detectors.js","tests/functional/helpers.js"]
Listening on 0.0.0.0:9000
Error: Tunnel failed to start: Exit code: 1
  at handleChildExit  <node_modules/digdug/Tunnel.js:336:16>
  at Socket.<anonymous>  <node_modules/digdug/Tunnel.js:379:6>
  at emitOne  <events.js:101:20>
  at Socket.emit  <events.js:191:7>
  at Pipe._handle.close [as _onclose]  <net.js:511:12>
Warning: Test failure; check output above for details. Use --force to continue.

and in the generated ./SauceLabsTunnel.log the last few entries are:

20170823 123219.209 [22439] ***********************************************************
20170823 123219.209 [22439] A newer version of Sauce Connect (build 3688) is available!
20170823 123219.209 [22439] Download it here:
20170823 123219.209 [22439] https://saucelabs.com/downloads/sc-4.4.9-linux.tar.gz
20170823 123219.209 [22439] ***********************************************************
20170823 123219.209 [22439] PROXY *** scproxy started ***
20170823 123219.210 [22439] PROXY found DNS server 127.0.1.1
20170823 123219.259 [22439] Started scproxy on port 40559.
20170823 123219.259 [22439] Please wait for 'you may start your tests' to start your tests.
20170823 123219.259 [22439] Starting secure remote tunnel VM...
20170823 123220.359 [22439] GET https://saucelabs.com/rest/v1/undefined/tunnels?full=1: HTTP response code indicated failure.
20170823 123220.359 [22439] Response: {"message": "Not authorized"}.
20170823 123220.359 [22439] Error checking overlapping tunnels.
20170823 123220.359 [22439] Cleaning up.
20170823 123220.360 [22439] Sauce Connect could not establish a connection.
20170823 123220.360 [22439] Please check your firewall and proxy settings.
20170823 123220.360 [22439] You can also use sc --doctor to launch Sauce Connect in diagnostic mode.
20170823 123220.360 [22439] Goodbye.

Tried this both locally and on travis-ci.org, thinking that perhaps the .travis.yml env section would help:

env:
  global:
  # SAUCE_USERNAME
  - secure: S/6Ild1n9SmW8xYqarjkigDqmyFgWS4Hi0M07e/ryPeS1MNQdiS5+WuSmlSTevM/wU/oSCvzXnKhO9W/1tvz4qj/BMQYxYWFjwWAXJrkjJPvWoa5ogYkR3ETSYrqdhkT+8LVof8iLPlpHjS1y2fozyJbYf1YNSkcVCLxMdIwnk0=
...

but got same output on both.

I'm doing this with latest version 2.8.2.

How do I get the functional tests on SauceLab to run?

Start by reading .travis.yml, tests/intern.js, and the functional test paths named in the issue to trace the SauceLabs configuration and required credentials. Document the account setup and configuration steps, then verify that grunt test can run the intern:functional task locally or in Travis.