A City Council committee moved forward with a ban on medical marijuana dispensaries Tuesday, approving a recommendation to outlaw storefront pot shops in Los Angeles while allowing small groups of patients and their primary caregivers to grow the drug on their own. The proposed ban comes after years of legal wrangling over how the city should regulate distribution of the drug. In 2007, the city imposed a moratorium on dispensaries, but a loophole allowed hundreds of new pot shops to proliferate.