R=bsiegert CC=golang-dev, remyoudompheng https://codereview.appspot.com/33650044
R=bsiegert, r CC=golang-dev https://codereview.appspot.com/14414044
testdata/, in anticipation of having other test data. R=dsymonds CC=bsiegert, golang-dev https://codereview.appspot.com/14361044