message: Add firefox dev, and make chrome and firefox use linux hosts
  Linux hosts are much faster at booting chrome, and in the case of dev, over 40
  seconds faster.
diff: },
  {
  - "browserName": "chrome",
  + "browserName": "safari",
  "platform": "OS X 10.10",
  + "version": "8"
  + },
  + {
  + "browserName": "safari",
  + "platform": "OS X 10.9",
  + "version": "7"
  + },
  +
  + {
  + "browserName": "chrome",
  + "platform": "Linux",
  "version": "dev"
  },
  {
  "browserName": "chrome",
  - "platform": "Windows 8.1",
  + "platform": "Linux",
  "version": "beta"
  },
  {
  {
  "browserName": "firefox",
  - "platform": "Windows 8.1",
  - "version": ""
  + "platform": "Linux",
  + "version": "dev"
  },
  {
  "browserName": "firefox",
  "platform": "Linux",
  "version": "beta"
  },
  -
  {
  - "browserName": "safari",
  - "platform": "OS X 10.10",
  - "version": "8"
  - },
  - {
  - "browserName": "safari",
  - "platform": "OS X 10.9",
  - "version": "7"
  + "browserName": "firefox",
  + "platform": "Linux",
  + "version": ""
  }
  ]
  