Before you pack your favorite vape juices for your next trip, take a few minutes to read up on local laws about vaping. While most states have age restrictions in place along with rules about vaping in public places, a handful of cities in the US are considering outright bans. San Francisco, which already prohibits the sale of flavored vaping liquids, is considering a proposal to ban the sale of all e-cigarettes in the city, which would make it the first such prohibition in the…