The PCR_flag and PCR value is in adaptation_field, not in payload.
The MSB of adaptation_field_control is used as whether adaptation_
field is exist or not.
For the case(PCR in only adaptation_field without payload), we modify
checking condition about adaptation_field_control field.
https://bugzilla.gnome.org/show_bug.cgi?id=778731
They often don't only contain the PCR information but also other
metadata, like title. Give this information to the pipeline.
Also strip the tags from the stream as we a) already parsed them now and
b) decoders don't like these tags to happen in the middle of the stream
(i.e. the start of each fragment) and tagdemux only can strip them off
the beginning and end.
