gzipdec: replace libarchive with zlib & allow for open ended streams

libarchive did not allow for open ended streams, and zlib is enough for
decompressing gzip data

Signed-off-by: Carlos Rafael Giani <dv@pseudoterminal.org>
umxparse: unref eos event

Fixes event leak

Signed-off-by: Carlos Rafael Giani <dv@pseudoterminal.org>
umxparse: Cleanup

Signed-off-by: Carlos Rafael Giani <dv@pseudoterminal.org>
umxparse: Push module data in chain function

This makes more sense than to push it in gst_umx_parse_read()

Signed-off-by: Carlos Rafael Giani <dv@pseudoterminal.org>
umxparse: Add more comments

Signed-off-by: Carlos Rafael Giani <dv@pseudoterminal.org>