gst-play: Add wait-on-eos option for image file playback

Since gst-play is stopping playback on EOS message, image file playback
is almost impossible until now. Not only for image file, this option
seems to helpful if an user wants to see the last frame.
15 jobs for show-on-eos in 54 minutes and 38 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Preparation
passed #202572
gst indent

00:00:30

passed #202571
manifest

00:00:34

 
  Build
passed #202587
build fedora x86_64

00:18:24

passed #202574
build nodebug fedora x86_64

00:03:22

failed #202573
build fedora x86_64

00:02:18

 
  Test
passed #202575
check fedora

00:02:44

 
  Full Builds
passed #202577
build cerbero android universal

00:11:38

passed #202578
build cerbero cross win32

00:07:57

passed #202579
build cerbero cross win64

00:06:04

passed #202576
build cerbero fedora x86_64

00:06:45

 
  Full Tests
passed #202583
valgrind bad

00:06:09

passed #202580
valgrind base

00:08:04

passed #202581
valgrind good

00:05:48

passed #202582
valgrind ugly

00:01:54

 
  Apps
passed #202584
android universal examples

00:09:49