hook_order can_update operation in uc_order_update_status never returns false

The 'can_update' operation is currently broken in hook_order(). See example where can_update should return false always, and the update op should never be displayed. I ran into this because for some reason i was still developing with ubercart BETA5 and when I was testing on a more recent version I was perplexed why updates were happening anyway.

I've taken the time to write a proper module_invoke_all() block instead of the $return = $function that's currently in uc_order_update_status().

Also, uc_order_view_update_form_submit() will always display "order updated" even if you can't update. This is a documentation issue and should probably fixed later with a warning issued instead.