MDL-42625 behat: Step definitions + related changes in features
In general aiming for compatibility with multiple browsers, firefox, chrome and phantomjs to be more specific. * Removing hardcoded waits * Adding @_alert, @_switch_window and @_switch_frame tags, to label actions that different drivers have problems with. * Adding missing @_files_upload and @_only_local tags to features that uploads files. * Fixing a few wait for page ready what specified miliseconds. * New methods to ensure elements (usual selectors), sections and editors are ready to interact with * Changing the select an option implementation to deal with the different drivers implementations when listening to JS events.