examples/ct: add AppendCertsFromPEMFile() util
examples/ct: add AppendCertsFromPEMFile() util

daviddrysdale/trillian,daviddrysdale/trillian,Martin2112/trillian,Martin2112/trillian,gtank/trillian,codingllama/trillian,AlCutter/trillian,RJPercival/trillian,daviddrysdale/trillian,google/trillian,codingllama/trillian,AlCutter/trillian,gdbelvin/trillian,google/trillian,gdbelvin/trillian,gdbelvin/trillian,Martin2112/trillian,RJPercival/trillian,gtank/trillian