Updated the settings pages to the new UI standard introduced in Spree 1.3.

Merge wasn't clean again due to spree translations.

Signed-off-by: Nathan Lowrie <nate@finelineautomation.com>

Conflicts:
	app/overrides/add_active_shipping_settings_tab.rb
	app/views/spree/admin/active_shipping_settings/edit.html.erb
	app/views/spree/admin/active_shipping_settings/show.html.erb
	config/locales/en.yml
Added an icon to the product packages tab entry.

I think the truck fits better than a barcode.

Signed-off-by: Nathan Lowrie <nate@finelineautomation.com>

Conflicts:
	app/overrides/add_packages_tab.rb
Gave the readme a long need updated.

Signed-off-by: Nathan Lowrie <nate@finelineautomation.com>

Conflicts:
	README.md