Test with Rails 4.2
Remove all warnings of invalid CSS selector
Add label to NO_STIP list of rails-dom-assertion

Related with rails/rails-dom-testing#15
Fix invalid selectors
Who cares about rubinius?
Use latest versions
Test with master
Assert the absent of tags not the escaped text

Nokogiri doesn't escape the output
Merge branch 'rails-4-2'

Conflicts:
	.travis.yml