Add open action
Add open action

Add 'git review open $change' to open a given review page in a
browser.

Change-Id: Ide46f7a34ef74c1979b3325494767fc549b187a7

entropia1/git-review,ka2m/git-review,openstack-infra/git-review,meelapshah/git-review,meelapshah/git-review,jeeloo/git-review