Michigan Gov. Rick Snyder signed a law Tuesday tightening a ban on direct sales of news cars, the latest in what Tesla (NASDAQ: TSLA) says are similar rules in states its says are protecting old fashioned auto dealers from the expanding electric automobile maker. It says state lawmakers in Michigan and other areas are passing anti-competitive legislation aimed at blocking Tesla's disruptive direct-to-consumer, no price-haggling sales method. Tesla, the Palo Alto maker of electric automobiles, recently…