Add "Check mail" menu items:

Accounts: Option menu->Check mail = check mail in all
   folders of all accounts
Accounts: Context (long-press on account) menu->Check mail = check mail
   in all folders of this account

Folder/Message List: Option menu->Check mail = check mail in all
   folders of this account
Folder/Message List: Contet (long-press on folder) menu->Check mail = check mail in this
   folder*

*All "Check mail" options, except for the long-press on an individual
folder, respect the normal synchronization class settings.

Eliminate all Refresh menu items.

Add progress indicators to Accounts activity.  Indeterminite progress
indicator while email checking is in progress.  Determinite progress
indicator while fetching unread counts.