Merge branch 'jc/send-email-reconfirm'

Validate interactive input to "git send-email" to avoid common
mistakes such as saying "y<RETURN>" to sender mail address whose
prompt is given with a correctly guessed default.

* jc/send-email-reconfirm:
send-email: validate & reconfirm interactive responses

diff --cc git-send-email.perl
Simple merge