The biggest challenge facing San Francisco Mayor Gavin Newsom's run for governor is not who's running the campaign, but whether he has enough money to keep the campaign going. Newsom, who has a full staff working the campaign, has raised $2.8 million with only about $1.1 million left in the bank.Meanwhile, Newsom's presumed major rival in the upcoming Democratic primary - Attorney General Jerry Brown, whose only staff is wife Ann Gust - has raised about $8 million, with roughly $7 million in the bank. And that's before he's officially declared, giving him the ability to hit up many donors...