Downcase s3_protocol configuration option to prevent bugs like https://gist.github.com/radar/5793814

As seen in: https://groups.google.com/group/spree-user/browse_thread/thread/152ceac667a80147
Remove check for overview link in homepage_spec
only show payment source form if source required

Fixes #3195
Test clicking logo in admin returns to /admin
Active coupon promos directly
Merge branch 'check_eligibility_for_create_line_items_promo_action' into 1-3-stable
Merge branch 'just_activate_promo_coupons' into 1-3-stable