#41 last message information in new mail command

[Robert Sowada]

Feature request by Tunc Gercek sent by mail:

I set up my preferences to run:

espeak -s 120 "New email"

I also noticed you can use %d to show the number of new messages, e.g.
in the "Show text" setting.

Are there any other "%" notations that can be used for other purposes,
such as the "From:" field or the "Subject:" field of the most recent
message, etc. For example, "%f" for "From:" and "%s" for "Subject:",
etc.

I could then use those in the "espeak" command line to read out who the
message is from, or what it's about, so I don't have to rush to my
computer each time I get a new email.