add tracing for BEGIN/COMMIT/ROLLBACK
add tracing for BEGIN/COMMIT/ROLLBACK

Traces the beginning and ends of transactions.
rickb777/gorp-old2,evenco/gorp,go-gorp/gorp,kevinc0825/gorm,losinggeneration/gorp,outdoorsy/gorp,mousesun/gorp,kevinc0825/gorm,rickb777/gorp-old2,yp-engineering/gorp,d-g-laptev/gorp,go-gorp/gorp,outdoorsy/gorp,d-g-laptev/gorp,yp-engineering/gorp,xiaoenai/gorp,GeertJohan/gorp,coopernurse/gorp,cortex/gorp,GeertJohan/gorp,losinggeneration/gorp,cortex/gorp,kimxilxyong/gorp,kimxilxyong/gorp,gabelula/gorp,xiaoenai/gorp,mousesun/gorp,gabelula/gorp,coopernurse/gorp,evenco/gorp