California Gov. Gray Davis (D) kept the green ink flowing yesterday by signing several more environmental measures into law. Perhaps the most significant of the laws — what Davis termed “the most ambitious” renewable energy standard in the country — requires that 20 percent of the electricity produced by private utilities in the state come from green sources by 2017. Enviros cheered the law, while current renewable energy producers called it overly complicated. Davis also gave his stamp of approval to a bill giving agricultural officials greater ability to regulate the application of pesticides within a quarter-mile of school grounds.