The owners of Clear Conscience Cafe in Central Square are on a mission. It’s pretty hard to miss… in fact, it’s conveniently spelled out on a poster behind the counter. They sell fair trade, shade grown, organic coffee and organic food “with an underlying agenda of social responsibility and environmental stewardship.” The counters are made of bamboo or crushed beer bottles; the ceiling tiles are made of 100% recycled material; the shop is illuminated......