It was an ambitious notion – now Californians will vote on a one-time 5% billionaire tax, and state’s super rich have pulled out all the stops in opposition One year ago, the idea of a billionaire tax in California was still in its infancy. It wasn’t yet one of the most contentious ballot measure fights in state history – pitting Democrats against Democrats, drawing national attention from political heavyweights, and netting hundreds of millions of Silicon Valley dollars to fight it. Back then, it was a bol…