Add capabilities to metadata during hook instead of fixture

Fix string formatting issue for remote server metadata

Add release date for v1.8.0

Updated release notes for v1.7.0

Remove test_invalid_credential for CrossBrowserTesting

Update release notes for v1.5.1

Restore accidentally deleted xvfb invocation in Travis CI

Restore accidentally deleted xvfb invocation in Travis CI

Update date of v1.4.0 in release notes

Bumped version number to 1.3.1 and updated release notes