Allow setting message security in send2-hook

Allow setting message security in send2-hook

This patch delays checking the message security options until after the user has an initial chance to edit the message.  This allows the security options to be set in a send2-hook when using $edit_headers.  Without this patch, the user has no way of automatically setting security based on recipients since the to/cc prompts are bypassed.

The other change in behavior is if the user happened to use a send2-hook to see if the message had security applied *prior* to editing the message, that no longer works.