Added a flag --strip_parameter_set_nalus. When enabled, parameter
set NAL units, SPS/PPS for H264 and SPS/PPS/VPS for H265, are stripped
from frames when converting NAL byte stream (AnnexB stream) to NAL
unit stream, which generates avc1/hvc1; otherwise they are not
stripped, and avc3/hev1 is generated.
Parameter set NAL units should not be stripped if they are varying
in the frames otherwise the frames may fail to be decoded.
The flag is enabled by default as we don't usually see varying
SPS/PPS/VPS and it is more space efficient with them stripped.
Set --strip_parameter_set_nalus=false to disable the flag if there
are varying SPS/PPS/VPS in the frames. This addresses #206.
Change-Id: I34bde6f33069f9f77d51a510b39f58a0f0e141aa
277c5b23c0