Added -p parameter to consider only a portion of the input header

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merge

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Disabled some pylint warnings to avoid false positive

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Used pylint disable command instead of disable-msg

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sampleftm.py and pixelfmt.py regenerated. Minor bug fix in make_enum.py

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pylint disable-msg is deprecated, we use disable instead

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one more test is expected to fail. Temporary.

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add Demuxer.flush() basic test

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actually implement the (stub of) Demuxer.flush().

Just a stub until the buffering semantics is sorted out.

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We now have sample formats

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detect and manage PyCParser parse error

suggest option -p as workaround (it was introduced just for that)
start to put error messages on stderr, in order to not
pollute the output, if any.

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always report the original path if -p is used.

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regenerate the enum

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add ref data for demuxer testing

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renamed for consistency

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rename : tests/data/bbb_as.ref => tests/data/bbb_sample_as.ref
rename : tests/data/bbb_vs.ref => tests/data/bbb_sample_vs.ref
add reference data for the full BBB.

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Merge ../pyrana