mention the createinstallmedia way to install yosemite. fix #16.
mention the createinstallmedia way to install yosemite. fix #16.

drduh/macOS-Security-and-Privacy-Guide,ScheerMT/OS-X-Yosemite-Security-and-Privacy-Guide,techraf/OS-X-Yosemite-Security-and-Privacy-Guide,drduh/OS-X-Security-and-Privacy-Guide,DeadLion/macOS-Security-and-Privacy-Guide,drduh/OS-X-Yosemite-Security-and-Privacy-Guide