* qatar/master:
  doc/avconv: replace forgotten av by avconv.
  avconv: reset input_ts_offset between files.
  doc/avconv: extend -ss documentation.
  avconv: call flush_encoders() from transcode() directly.
  avconv: fix broken indentation.
  avconv: rescue poor abused limit_filesize global.
Merged-by: Michael Niedermayer <michaelni@gmx.at>