TestCafe 1.6.0 compatible

• Possible to use either string or string[] as src property
• screenshot options are nested in the screenshot property:

"screenshots": {
    "path": "./target/testreport/screenshots",
    "takeOnFails": true,
    "pathPattern": "test-${TEST_INDEX}-${FILE_INDEX}_${QUARANTINE_ATTEMPT}",
    "fullPage": false
}