Add back 'refresh' and 'settings' to folder context menu.

Both items are commonly used even by the average user (and likely both
are used more commonly than 'clear local messages'), so it makes
sense to provide them in the context menu as well as the action bar.
Add back account settings to account context menu.
Merge pull request #224 from maniac103/extend-folder-menu

Add Refresh' and Settings to folder context menu.

Also add Account Settings to the account context menu.