Setting minimal MAC OS deployment target to 10.9

We cannot set it to any earlier version because of strange libstdc++ behaviour.
So for now setting to 10.9 just to know how old versions we can support.
8 jobs for master in 3 minutes and 6 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #7728
linux
build:linux

00:01:54

passed #7727
mac_old
build:mac

00:02:22

passed #7726
win32
build:win32

00:02:42

passed #7725
winxp
build:winxp

00:02:34

 
  Dist
passed #7732
linux
dist:linux

00:00:05

passed #7731
mac_old
dist:mac

00:00:24

passed #7730
win32
dist:win32

00:00:19

passed #7729
winxp
dist:winxp

00:00:17