The three Democrats running for governor are rolling out various proposals.  Political newcomer Clay Pell says the goal of his economic plan is to invest in education and maintain a high-quality infrastructure.  Providence Mayor Angel Taveras is proposing low or no-interest loans to cities and towns to repair schools, roads and bridges.  And state Treasurer Gina Raimondo wants to create The Rhode Island Green Bank and Clean Energy Finance Authority to provide financing for renewable energy and energy-efficiency projects.