Fix #6372

closes #6279

This conversion is done by Transpec 2.3.6 with the following command:
    transpec features

* 19 conversions
    from: obj.should
      to: expect(obj).to

* 1 conversion
    from: == expected
      to: eq(expected)

For more details: https://github.com/yujinakayama/transpec#supported-conversions

* removed wait_until where possible
* replaced wait_until with DOM obersavtions
* added match: :first to all finders that assumed getting the first element
* replaced evaluate_script with execute_script where possible
* replaced a few execute_script with DOM observations through Capybara
* removed sleep where possible
* replaced sleep with DOM obersvations
* replaced "wait for ajax" with DOM obersavations
* replaced alert confirmation with new selenium API
* bump selenium webdriver
* made any other fixes to get green again

- for before/after comparisons,
including rake tasks for easily generating the images from command line

This reverts commit c52342b7.