Kick off post 1.7.11 cycle

I haven't decided what to call this one, 1.7.12, 1.8.0, or even 2.0.
Given that summer is a relatively slow season, I suspect 1.7.12 is
the most likely outcome, but we will see.

Signed-off-by: Junio C Hamano <gitster@pobox.com>