Adapt mail capture to support mailto URI

This is to prepare this function to be called from other programs as a
mailto: handler
Enable narrow-to-region permanently
Separate faces for region and paren-match
Rewrite the archiving function, can be just for DONE atm

Adding notes, which I have enabled when cancelling items, is
implemented by runnin a post-command hook, which means the adding of
the note is always the last to run. I could not get the archiving to
be the last action to run.
Replace car -> first and cdr -> rest
Configure mailto handler