added pre and post run hooks.
added pre and post run hooks.

akutz/cobra,abhishekgahlot/cobra,jlowdermilk/cobra,jrossi/cobra,liggitt/cobra,vikstrous/cobra,sdomino/cobra,eparis/cobra,k4rtik/cobra,spf13/cobra,anthonyfok/cobra,gosuri/cobra,nicrioux/cobra,simlelievre/cobra