gobuilder: ignore _test.go files when looking for docs, more logging
gobuilder: ignore _test.go files when looking for docs, more logging

R=n13m3y3r
CC=golang-dev
http://codereview.appspot.com/4918050
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go