rtmpproto: Track last received timestamp

Some RTMP commands need the most recent timestamp as their parameter, so
keep track of it. This must be the most recent one and not e.g. the max
received timestamp as it can decrease again through seeking.

Signed-off-by: Martin Storsjö <martin@martin.st>
rtmpproto: Add pause support

Signed-off-by: Martin Storsjö <martin@martin.st>
Merge commit 'f4cd8b80b9cb2a9a4112d8abb1d3b93cd3b4e467'

* commit 'f4cd8b80b9cb2a9a4112d8abb1d3b93cd3b4e467':
  rtmpproto: Track last received timestamp

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '9bec3ca2b878c83d2337bc6095bd51c3e3f8eef0'

* commit '9bec3ca2b878c83d2337bc6095bd51c3e3f8eef0':
  rtmpproto: Add pause support

Conflicts:
	libavformat/version.h

Merged-by: Michael Niedermayer <michaelni@gmx.at>
urlprotocol: remove unused url_interrupt_cb declaration

It is a remnant of the old interrupt callback API.
Merge commit 'fb238f8230c1b0314985482207add548c68f83cf'

* commit 'fb238f8230c1b0314985482207add548c68f83cf':
  urlprotocol: remove unused url_interrupt_cb declaration

Merged-by: Michael Niedermayer <michaelni@gmx.at>
tests/fate/mpeg4: add -sws_flags +bitexact

Should fix fate-mpeg4-resolution-change tests

Found-by: ubitux
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>