update screenshots from 3.x branch

.../UI/expected-screenshots/CustomVariables_link_in_menu.png

.../tests/UI/expected-screenshots/CustomVariables_manage.png

...tests/UI/expected-screenshots/SimpleUITest_simplePage.png

...I/expected-screenshots/SimpleUITest_simplePagePartial.png

.../UI/expected-screenshots/ActionsDataTable_auto_expand.png

...I/expected-screenshots/ActionsDataTable_column_sorted.png

...ed-screenshots/ActionsDataTable_configuration_options.png

...d-screenshots/ActionsDataTable_exclude_low_population.png

tests/UI/expected-screenshots/ActionsDataTable_flattened.png

tests/UI/expected-screenshots/ActionsDataTable_initial.png

...ted-screenshots/ActionsDataTable_pageview_percentages.png

tests/UI/expected-screenshots/ActionsDataTable_search.png

...I/expected-screenshots/ActionsDataTable_search_closed.png

.../expected-screenshots/ActionsDataTable_search_visible.png

...ed-screenshots/ActionsDataTable_segmented_visitor_log.png

...eenshots/ActionsDataTable_segmented_visitor_log_hover.png

...xpected-screenshots/ActionsDataTable_subtables_loaded.png

.../UI/expected-screenshots/ActionsDataTable_unflattened.png

...eenshots/ActionsDataTable_unique_pageview_percentages.png

tests/UI/expected-screenshots/BarGraph_load.png