Merge branch 'mt/send-email-cover-to-cc'

* mt/send-email-cover-to-cc:
t9001: avoid non-portable '\n' with sed
test/send-email: to-cover, cc-cover tests
git-send-email: two new options: to-cover, cc-cover

diff --cc Documentation/git-send-email.txt
Simple merge

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