civimail with workflow enabled: scheduled to approved step and search based mailings

when workflow is enabled for civimail, we implement some alternative redirections at various steps. there are two issues that need to be improved:

1) for search-based mailings, continuing after the scheduled step returns you to the search results. but there is the additional approval step required, and returning to the search results is misleading (the user things the process is complete). we should only return to the search results if workflow is not enabled.

2) the normal behavior after scheduling is to return to the sent/scheduled page. from there, the user can click to approve/reject. but we really should redirect to the approval page as part of the multi-step process, rather than return to the sent/scheduled page. we should only return there if the logged in user does not have approval perm.

i will submit patches for this, but want the core team to weigh in on the specs first.