Having "wvtt" in the codec string (in the master playlist) causes
errors on some older Apple products. As including it is optional,
we are opted to omit it to ensure support for all Apple products.
Close#402
Change-Id: Ib1072bcc26a3ff66e3a6d3204789c0c8c678d4db
Create an end-to-end test for ad cues. This test's final result is not
correct but illustrates the problem we have in the cue insertion and will
be fixed by a later CL.
Change-Id: Ia8b43a53848941be52cf9ade018668e6477e8df2