Delete user and hook confusion when deleting users in Multisite

[andreasnrb]

Currently:
The hook wpmu_delete_user fires when deleting user in Super Admin->Users.
The hook remove_user_from_blog when deleting user under site Users->Authors & Users.
In standard WP:
The hook delete_user is called when deleting users it should be the same in MultiSite when deleting from Super Admin->Users.
Or add new hooks and deprecate previous.
delete_user_from_network for when deleting a user totally.
delete_user_from_site for when deleting a user from a specific site. This is hook also then fires in non-MultiSite mode since that then corresponds to one site.