refactor ActiveAdmin.flash
make ActiveAdmin.flash’s closable
close after attr for js flash messages
remove formtastic locale keys
use formtastic_i18n gem
fix feature for devise text change
remove focus: true from some specs
use a more common initializer name
fix breadcrumb link when path passed without leading slash
Merge pull request #3469 from timoschilling/fix_specs_for_devise

fix feature for devise text change
Merge pull request #3415 from timoschilling/i18n_remove_formtastic

remove formtastic locale keys
Merge pull request #3492 from dmitry/fix/breadcrumbs-leading-slash-may-be-left

Fix breadcrumb link when path passed without leading slash
Merge branch 'pr/js_flash'
Merge branch 'pr/remove_focus'
Merge pull request #3488 from timoschilling/engine_initializer

use a more common initializer name
remove i18n key `active_admin.update_model`

This key is not used by active admin, see #3172
remove i18n key `active_admin.create_model`