Was consistently timing out in IE8 on XP.

Shooting in the dark, in hope to resolve consistent error
"[element.text()] Error response status: 13, , UnknownError - An unknown server-side error occurred while processing the command.
Selenium error: unknown error: Cannot read property 'OTransform' of null\n
  (Session info: chrome=30.0.1599.114)\n
  (Driver info: chromedriver=2.4.226074,platform=Linux 3.13.0-83-generic x86)","status":13,"cause":{"status":13,"sessionId":"92f393cc5c354032a0a3f9846fc70a8d","value":{"message":"unknown error: Cannot read property 'OTransform' of null\n
  (Sessi..."

Mobile safari errored The Sauce VMs failed to start the browser or device.
Docs say more fields are required
https://wiki.saucelabs.com/display/DOCS/Test+Configuration+Options#TestConfigurationOptions-RequiredAppiumTestConfigurationSettings
and this helped.

Safari 6 on OS X 10.8 and IE 8 on Win XP are not available.
Platform configurator still offers them
https://wiki.saucelabs.com/display/DOCS/Platform+Configurator#/
but https://saucelabs.com/platforms shows these OSes are
no longer supported (both are long EOL anyway).

Closes #170.
It fails on title becoming set from first line.
Bumping 4.4->5.0, 10s->20s, didn't help.
But manual testing shows Mathdown does load & render math.

For #173, I urgently need CI that can give me pass/fail,
and Android is not very usable anyway (#81), so commenting out.