twitterDamn you! (Credit: Getty Images) There’s an oft-repeated claim these days that San Francisco is up for sale to the highest bidder. We’d say that seems to be the case when scores of parking spaces in the Civic Center are closed off for a Twitter conference, but payment to the San Francisco Municipal Transportation Agency is a mere $1,194. Bill Graham Civic Auditorium was the site Wednesday of a one-day conference called Flight, put on by Twitter for mobile developers. At the request of conference producer Another Planet Entertainment, the SFMTA gave the go-ahead for signs to be posted notifying drivers they’d be towed if they parked on Grove between