aggregator: Add live mode to working on live mode

In this mode, aggregator will generate output only in
PLAYING state as if it's live source element. Also, start
time (segment.position) will be updated using pipeline's running
time regardless of start-time-selection mode, meaning that
the start-time-selection property will be ignored.
34 jobs for !603 with aggregator-live in 2 minutes and 21 seconds (queued for 59 seconds)
latest detached
Status Job ID Name Coverage
  Build Docker
passed #4185196
alpine amd64 manifest builder docker

00:00:27

passed #4185195
android docker

00:00:22

passed #4185194
cerbero fedora amd64 docker

00:00:26

passed #4185193
fedora amd64 docker

00:00:37

passed #4185197
gst-indent amd64 docker

00:00:51

 
  Preparation
passed #4185199
gst indent

00:00:56

manual #4185198
manual
manifest
 
  Build
created #4185208
gstreamer
build cerbero cross-android universal
created #4185212
gst-ios-13.2
build cerbero cross-ios universal
created #4185209
gstreamer
build cerbero cross win32
created #4185210
gstreamer
build cerbero cross win64
created #4185207
gstreamer
build cerbero fedora x86_64
created #4185211
gst-macos-10.15
build cerbero macos x86_64
created #4185203
build clang fedora x86_64
created #4185206
1809 windows docker allowed to fail manual
build msys2
created #4185200
build nodebug fedora x86_64
created #4185201
build static fedora x86_64
created #4185202
build static nodebug fedora x86_64
created #4185204
1809 windows docker
build vs2017 amd64
created #4185205
1809 windows docker
build vs2017 x86
 
  Test
created #4185213
gstreamer
check fedora
created #4185214
gstreamer
integration testsuites fedora 1/4
created #4185215
gstreamer
integration testsuites fedora 2/4
created #4185216
gstreamer
integration testsuites fedora 3/4
created #4185217
gstreamer
integration testsuites fedora 4/4
created #4185222
gstreamer
valgrind bad
created #4185219
gstreamer
valgrind base
created #4185218
gstreamer
valgrind core
created #4185223
gstreamer
valgrind ges
created #4185220
gstreamer
valgrind good
created #4185221
gstreamer
valgrind ugly
 
  Integrate
created #4185224
cross-android universal examples
created #4185226
gst-ios-13.2
cross-ios universal examples
created #4185225
documentation