[MlMt] Selector to set online state of specific account?

[Rob Wells]

There are currently keybinding selectors to toggle the online state of the current account or all accounts, but is it possible (or would it be practical?) to toggle the online state of a specific account (specified by UUID)?

My use case is that I have both personal and work accounts in MailMate, and have a keyboard shortcut to toggle the online state of the work accounts. Currently this is achieved by pairing `goToMailbox:` with `toggleOnlineState:` and then finally prompting to open a mailbox to move on from the last mailbox moved into.

Here is the current shortcut definition for the curious (with the first key of the chord omitted):

	"w" = (
		"goToMailbox:",
		"imap://account1@example.com",
		"toggleOnlineState:",
		"goToMailbox:",
		"imap://account2@example.com",
		"toggleOnlineState:",
		"goToMailbox:",
		"imap://account3@example.com",
		"toggleOnlineState:",
		"goToMailbox:" // Prompt for where to go now.
	);

Very best wishes,
Rob