Why does my new switch keep tripping the breaker?
You have a new-style switch loop -- the current (2014) NEC now requires switch loops to have a neutral, not just a hot and a switched.  Switch the black and red wires on the light, and the white and red wires on the switch -- this means the light goes to red and white, and the switch goes to black and red, with the white wire in the switch box capped off with a wirenut.

(The reasoning behind the new requirement is to allow future timers, dimmers, and other such "smart" switching devices to be designed in a more sane manner where they can draw power for their own operation in a normal way, instead of trying to turn their load on slightly at all times or sending that working current back through the equipment grounding system.)