tree.h: K&R formatting and typo cosmetics
tree-test: Refactor and plug memory leaks

With the most annoying memory leak found by Derek Buitenhuis.
avfilter: Add some missing FF_API_AVFILTERBUFFER ifdefs
rtpenc: Simplify code by introducing a macro for rescaling NTP timestamps

Signed-off-by: Martin Storsjö <martin@martin.st>
rtpproto: Support nonblocking reads

Signed-off-by: Martin Storsjö <martin@martin.st>
rtpproto: Remove a misplaced comment

The fdset is a pollfd array nowadays, and it is already populated
at this point.

Signed-off-by: Martin Storsjö <martin@martin.st>
rtpproto: Simplify the rtp_read function by looping over the fds

This avoids having duplicate code where only the fd parameter
differs.

Signed-off-by: Martin Storsjö <martin@martin.st>
rtpproto: Move rtpproto specific function declarations to a separate header

Mixing these with the rtp depacketizer functions in rtpdec.h is
no good.

Signed-off-by: Martin Storsjö <martin@martin.st>
avopt: Check whether the object actually has got an AVClass

AVIOContext has got an av_class member that only gets set if
opening the context using avio_open2, but not if allocating a
custom IO context. A caller that wants to read AVOptions from
an AVIOContext (recursively using AV_OPT_SEARCH_CHILDREN) may
not know if the AVIOContext actually has got a class set or not.

Signed-off-by: Martin Storsjö <martin@martin.st>
avconv: Call exit_program instead of exit in avconv_opt as well

This seems to have been missed in 636ced8e1dc.

Signed-off-by: Martin Storsjö <martin@martin.st>
avconv: add -n option to immediately exit when output files already exist

Signed-off-by: Martin Storsjö <martin@martin.st>